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 A336691 #8 Jul 31 2020 16:42:47 %S A336691 1,1,1,1,1,1,1,1,2,1,1,1,2,1,1,1,1,2,2,1,2,1,1,1,1,1,1,2,1,1,2,1,1,2, %T A336691 1,2,2,1,2,2,1,1,2,2,1,1,1,1,2,2,1,2,2,1,1,1,1,2,1,1,2,1,3,1,2,2,2,1, %U A336691 1,2,1,2,2,2,1,2,1,1,1,2,2,1,2,2,1,2,1,1,2,2,1,1,2,2,1,2,2,2,1,2,1,2,3,1,1 %N A336691 Number of distinct prime factors of 1+sigma(n). %H A336691 Antti Karttunen, <a href="/A336691/b336691.txt">Table of n, a(n) for n = 1..65537</a> %H A336691 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A336691 a(n) = A001221(1+A000203(n)) = A001221(A088580(n)). %o A336691 (PARI) A336691(n) = omega(1+sigma(n)); %Y A336691 Cf. A000203, A001221, A088580, A058062, A332459, A336692, A336693, A336694, A336695. %K A336691 nonn %O A336691 1,9 %A A336691 _Antti Karttunen_, Jul 31 2020