What is the next term in this sequence?
Hint: Read the numbers aloud!
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
This sequence is called a " Look & Say " sequence, a type of notational sequence, which obeys the following rule:
1 : Start with a seed value a 0 .
2 : Read the number of groups of consecutive digits (i.e. 1 2 1 1 2 3 is read "one 1 , one 2 , two 1 s, one 2 , one 3 ").
3 : Write down the resulting digit (i.e. 1 1 1 2 2 1 1 2 2 3 ).
4 : Repeat.
3 1 2 2 1 1 can then be written as "one 3 , one 1 , two 2 s, two 1 s", which gives 1 3 1 1 2 2 2 1 .
Notice that when a 0 = 2 2 , any output a i = 2 2 .
Note: This sequence was studied by John Conway, who discovered, among many other characteristics, that when the sequence approached ∞ and that the seed value a 0 = 2 2 , L n L n + 1 equaled a constant λ ≈ 1 . 3 0 3 5 7 7 2 6 9 . . . , where L i is the number of digits in the i th element; λ is called Conway's constant .