This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A366636 #15 Jan 20 2024 12:19:11 %S A366636 1,1,2,2,2,3,4,3,3,3,4,3,5,3,3,5,3,2,5,3,4,6,5,2,4,4,4,4,6,2,8,4,4,6, %T A366636 5,9,8,3,3,7,6,5,6,8,5,10,6,2,6,10,8,6,5,5,8,10,8,7,6,5,9,2,5,12,4,7, %U A366636 11,4,5,6,8,3,9,4,3,9,7,10,8,5,6,8,5,3,12 %N A366636 Number of distinct prime divisors of 7^n + 1. %H A366636 Max Alekseyev, <a href="/A366636/b366636.txt">Table of n, a(n) for n = 0..387</a> %F A366636 a(n) = omega(7^n+1) = A001221(A034491(n)). %t A366636 PrimeNu[7^Range[0,84] + 1] (* _Paul F. Marrero Romero_, Nov 11 2023 *) %o A366636 (PARI) for(n = 0, 100, print1(omega(7^n + 1), ", ")) %Y A366636 Cf. A034491, A001221, A057937, A227575, A366632, A366637, A366638, A366639. %Y A366636 Cf. A046799, A366580, A366605, A366615, A366627, A366655, A366664, A119704, A366686, A366712. %K A366636 nonn %O A366636 0,3 %A A366636 _Sean A. Irvine_, Oct 15 2023