More on ϕ \phi in 2016

Find the minimum value of k k that makes y y an integer.

y = log ϕ ( 3 0 3 ) ( 3 0 k d 3 0 3 ϕ ( d ) ) \large{y= \log_{\phi(30^3)}\left(30^k \prod_{d \mid 30^3}\phi(d)\right)}

Notation : ϕ ( x ) \phi(x) denotes the Euler totient function .


Inspiration .


The answer is 48.

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1 solution

Trevor Arashiro
Jan 9, 2016

If x = i = 1 n a i k x=\prod_{i=1}^{n} a_i^k where each a i a_i is a distinct prime.

d x ϕ ( d ) = ( ϕ ( x ) ) ( k + 1 ) n ( k + 1 ) n 1 × ( x ) k ( k + 1 ) n 2 ( k + 1 ) n + ( k + 1 ) n 1 \large{\displaystyle \prod_{d \mid x}\phi(d)=\left(\phi(x)\right)^{(k+1)^n-(k+1)^{n-1}}\times (x)^{\frac{k(k+1)^n}{2}-(k+1)^n+(k+1)^{n-1}}}

Here k = 3 , n = 3 k=3,~n=3

beat me to the solution(by a day)! you should prove it though(the claim).

Aareyan Manzoor - 5 years, 5 months ago

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