So, if you didn't know, it's possible to compute the last \(n\) digits of the Graham's number quite easily, by observing the fact that
3↑3=...7,
3↑3↑3=...87,
3↑3↑3↑3=...387,
3↑3↑3↑3↑3=...5387, and so on.
In fact, if you search on the internet you'll find several people that computed up to 200 digits, 400 digits, or 500 digits.
Now, I admit I was pretty disappointed with this results. I couldn't find anyone that pushed up the calculations! (I may be wrong, in that case show me if anyone else actually calculated more than that)
So, I developed an algorithm that is sufficiently efficient to compute the first 500 digits in only approximately 2 seconds. With this algorithm, I was able to compute the last 10000 digits of Graham's number on my computer, in 16316.5 seconds (approximately 2.2 hours).
I'm not entirely sure how, but I'm pretty sure it's possible to make the algorithm much more efficient than that, so that even calculating these digits should happen in a matter of few seconds. If you have any good ideas, tell me below (try it first, if possible).
Either way, here they are (new line every 70 digits):
g64=...3078726077030301309631860565499591166728394144521822940211684925744690830316086262130785618226100420312968346787242002533570716504288288603815278905831777347434889993632217093771887053021613400826231041652609872469522381180520893701095105746695201447806881045566940953003050207963025108931458177782068496837757322945657846959175109945261571525815313383171441763572462779809715173494067855792793530636179937522573612820301473864489406090828511196812234883812826536412935235758505566522273299851386708985575844764837111577945400718863148653461185413076846495408383358058416954122807660380207115535268270916958794751064250768903277826708848390877435531688133831988779505683625673270427786212688069705881027617402863937895213427659682817417461057075479776076397517703824469120630243109151731515546720207203298057792145699917956905186596024469027274217279141430415867319657287140268008652315291316261820652195021921091461070451907392628396743433966206832681974497464193534150297618059752197469899167905539512407496240223067753651132002278170502842273671497491794032802699070161003317178855043208655046184676579497958334888729380961765982723506737351365624129933561592420403366586026376463513644509019651699124680317010358130680488712325198535829916206382631701477832698324585503287762867838791720029901423547073086007824609234282758224908436213000920393765646265795808696449402378032391693584514586845743500193087499932962375893178562196090339426243848085176276584372829470728254599948415970659821958864982353541909598033354078979538256357245359747368737720544909862394110578904843360397740815782128903796684805343101612454474591654101650693961377271882775445851973967815729796266594738946097169571922151724219229759670392571616731391424780277194256133384190907030138393942902314563283858812497613727950277408609617924467961860253763582154973363203811166858264982706857348079908854558691236991819878323695993552951130721247635787520841764173839071101104122258672751922892887196430745328215426144487175008095242123636376813961077749523532016833501424281091368978529043131788135333355110889022359477210715849496037260619984908856098462387682166967457951388588832356929998573679542011111185463440443504567679401356765457595958899512304618723436035217938891962050267508864234897311954162655416856563460135194869521209403751415314099407271948277374441254695053697070411390864858720859625554195903023806062913716913872285547779439802507677323967059172076874746728446540634181380341294304360976602155423367112057390817423461175744118240134002338774237104408010940301648706232749183781478765763754598101538214087714922326451525832690110799166775443442353837481547403100880637946597552737840758546298403351731162182383124376404468239965615920828447876334410730503146643034564958892386400206720157774336643971046097191339778671192707610935976126970111864008832421411157351854252317530184373336024446785108592281094794328081763872749469924679447544621513505367844082852088230997958080227897832298874619826542016735413058821008184742832774323554162170468091396741777275954763659384746126135206252864936155799330878658837275030231698460626243816863158237685462668066944052359344981816230189301309354006700248433587219900315863936527371581966011826743819385582719223648840620249884709395919441012031404522773151579351525369364934250530932709877378035492327740781679794020867401382441063153368792024085513096521839198783970159526194524749783176345096613835421534080777992741043623054920589996619189747939500280803206850527988771449843650854426749054486992798433092391599973744959029957588363427364161563026748153852589303542350028921428192299937990553925840346317974076455080900183501257672002542134775436857784125821479348208852835284734463951445497740069154757001473626293563964115997450637632591207602085065331518191297627524916528283327470445487220431209794181800837524288180786740953625707023916128625574340099420494628683883364612475194501407401023508584105029555399601882357799580811904419558955154139962907362641416032599108674402147606737302706859009869989241966114092477240778997675158599361406185035698654419625238203492758967623899121555785944392474204282770185404329679131806504016165468217196445509364500595583090752015617577969861470976788938740200600298288287888330891308863372281972862545180083840021672484219663987467329507766983318084471821793411710053202996739234042899808568275434578072780336225074554635303452502047026773318085940276837031308524437227254648631365299090852540852736811700598925661498015963926725007451760685374013593406210074607565408138965932473526208240166197001865513821872977219498463169007490827378094264056082839271636552848839603826288292359895120699259424392975074982181643783346324645455176373275765527676059058269397249692453299809233801905518318024634168876185410488177562238555312340229579691441224836406466849925916755964304671002296817244339224792182135995868969341492369077624305677016482250204198347030671629689692261860404690895448588913482752746673155208558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4195387
#NumberTheory
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2^{34}
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Update: I just found a site that lists exactly the same digits, so I'm definitely not the first to have calculated this digits. Still, the efficiency question remains.
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what is the inverse of grahams number
1/243=0.004115226337448559670781893004115226337448559670781893004.... , period=27, and etc
Testing Math Editor: π
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Booya! eiπ+1=0
what's the algorithm?
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The most efficient algorithm I thought for now is just one line on Mathematica:
calc = 3; Do[calc = PowerMod[3, calc, 10^i], {i, 1, 500}]; calc
This computes the latest 500 digits correctly in roughly 0.7 seconds on my computer. For 1000 digits, it takes 6.2 seconds. The main problem with this algorithm is that it gets progressively much slower since it computes all the already computed digits with every calculation. There must be a way to avoid recomputing all the digits every time, for example to get the 1001st digit pretty much instantly just by knowing the latest 1000 digits, but I can't quite figure out how.
3.345625467385246375823675867348259426395436858685673245678845673333302367489236758493678624396724839674839678492456789106574385627384562385962785967289674280654803333221...
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what a constant look at the digits ......31579315973175917973999717329......
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started decimal place 46374
it had a lot of odds and 1 even
another: 4.12344678259467589436578249365782493333331029564782936758293672892345636758935674392567238962789434247148245623392564839578123456123456925379267896661154673845268012345679213....
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look at the digits .....56278524678333333333333...(100 3s total)...333333335326845367823524832352784325682283683678335683.....
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started decimal place 142857
1/3=0.33333333333333333333333333... (period 1),1/9=0.111111111111111111111111111111... (period also is 1),1/27=0.037037037037037037037037037037037037... (period=3),1/81=0.01234567901234567901234567901234567901234567901... (period=9),...,1/grahams number (period=grahams number/9)
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period triples
546738111123/999999999999
23456/99999 (period=5)
5.15673842536784536758786946875047894037580204308200206392579239563853633333026790678042606596503768034768013999761111124910123...
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find the digits ......3159735193759135793133331759173979973197351973113373313579197315793139735193791735931597391375975973797735179...... (all the digits here were odd)
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started decimal place 999001
umm the number 26378146328956830967280674283967389657849306784230673289567807685240677773333506342657802367819567483578695487530247483120657483075101 is this prime? try in Number world
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It's divisible by 7
6.546728567584673256743295627438956784396578234967329647812967489367850163478046780654738563478056237480628111333999777546738146713294672946170856173805617438056173805637850613785061795714380561379461378463785016437586071483674820365780476892071520773457215893657896574839678964723911011...
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you could see the digits: ......658963725933333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333674382956743286972678594310001647193......
periodic sequence: 0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,... (period=2)
3,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,2,4,... (period=2) but i have a 3 at the start
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what a periodic sequence
5.6574891673895617834523784016478301357835631756347827468203567813647813257803657830573205417329536780513728140613751376037805617834178203567318065354721054273805723104617357328033336217304617358016785203675830682306473280567281036478036121111615783236718036701561111116163781526783106732806512051627780254167394394567956293567239456379452367945231755547956371453925781936478329615782306712065720567203...
1.128283173717379590959517773101717618496378493678149367192657839641789463786437859367489657329467381596378406378057381940785901674023748023671802367148023647820367328407895036274810738406738407384063578032748036258407389506328051020408160904010025062523549823647839567194678329678162835063810463278047328140333316703267023647382067124036721507132940738947389432691034758903751932075819403673027810635695679579693103446748617840672046738056713046783210467328036748105780637840632758023456167498146273849326758946738239215623749123401... is irrational approximations 9/8,35/31
hi