A333341 - OEIS

%I #7 Apr 15 2020 00:13:04

%S 1,1,4,1,5,5,16,5,4,5,9,5,5,17,5,5,11,11,16,5,16,9,2,5,25,5,4,17,74,5,

%T 56,21,16,11,100,29,13,101,5,5,43,17,27,9,40,61,8,5,32,25,11,5,28,29,

%U 45,61,16,149,21,5,3,63,58,53,5,47,75,133,4,145,76,29

%N a(n) is the smallest positive number k such that n divides 5^k - k.

%C For any positive integer n, if k = a(n) + n*m*A007736(n) and m >= 0 then 5^k - k is divisible by n.

%F a(5^m) = 5^m for m >= 0.

%o (PARI) a(n) = for(k=1, oo, if(Mod(5, n)^k==k, return(k)));

%Y Cf. A007736, A072872, A333336, A333339, A333340.

%K nonn

%O 1,3

%A _Jinyuan Wang_, Apr 14 2020