A366717 - OEIS

%I #11 Oct 26 2023 08:42:44

%S 11,11,11,5,11,7,11,5,11,11,11,5,11,11,11,5,11,7,11,5,11,11,11,5,11,

%T 11,11,5,11,7,11,5,11,11,11,5,11,11,11,5,11,7,11,5,11,11,11,5,11,11,

%U 11,5,11,7,11,5,11,11,11,5,11,11,11,5,11,7,11,5,11,11,11

%N Smallest prime dividing 12^n - 1.

%C Periodic with period 12, repeat of 11, 11, 11, 5, 11, 7, 11, 5, 11, 11, 11, 5.

%F a(n) = A020639(A024140(n)). - _Paul F. Marrero Romero_, Oct 25 2023

%t Table[FactorInteger[12^n - 1][[1,1]], {n,71}] (* _Paul F. Marrero Romero_, Oct 25 2023 *)

%Y Cf. A024140, A366718, A366719.

%K nonn

%O 1,1

%A _Sean A. Irvine_, Oct 17 2023