A366651 - OEIS

%I #10 Jan 09 2024 18:46:53

%S 1,2,2,4,3,4,3,6,3,6,4,8,4,6,6,9,5,6,4,11,6,8,4,12,7,7,6,12,6,11,3,12,

%T 8,10,10,12,6,8,9,15,5,11,5,14,10,8,6,17,5,13,8,16,8,12,10,17,7,10,6,

%U 21,5,7,9,15,8,15,6,19,9,20,7,18,7,12,14,16,9

%N Number of distinct prime divisors of 8^n - 1.

%H Max Alekseyev, <a href="/A366651/b366651.txt">Table of n, a(n) for n = 1..500</a>

%F a(n) = omega(8^n-1) = A001221(A024088(n)).

%F a(n) = A046800(3*n). - _Max Alekseyev_, Jan 09 2024

%o (PARI) for(n = 1, 100, print1(omega(8^n - 1), ", "))

%Y Cf. A024088, A001221, A057953, A366652, A366653, A366654.

%Y Cf. A046800, A133801, A366604, A366611, A366620, A366632, A366660, A102347, A366681, A366707.

%K nonn

%O 1,2

%A _Sean A. Irvine_, Oct 15 2023