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 A325636 #8 May 21 2019 22:03:39 %S A325636 1,1,2,1,2,12,2,1,1,2,2,4,2,4,6,1,2,3,2,2,2,4,2,12,1,2,2,56,2,12,2,1, %T A325636 6,2,2,1,2,4,2,10,2,12,2,4,6,4,2,4,1,1,6,2,2,12,2,8,2,2,2,24,2,4,2,1, %U A325636 2,12,2,2,6,4,2,3,2,2,2,4,2,12,2,2,1,2,2,56,2,4,6,4,2,18,14,8,2,4,10,12,2,1,6,1,2,12,2,2,6 %N A325636 a(n) = gcd(2n, sigma(n)). %H A325636 Antti Karttunen, <a href="/A325636/b325636.txt">Table of n, a(n) for n = 1..65537</a> %H A325636 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A325636 a(n) = gcd(2n, A000203(n)). %F A325636 a(n) = gcd(2n, A033879(n)) = gcd(sigma(n), A033879(n)). %o A325636 (PARI) A325636(n) = gcd(n+n,sigma(n)); %Y A325636 Cf. A000203, A009194, A033879, A325385, A325635, A325637 (n such that a(n) = 2n). %K A325636 nonn %O A325636 1,3 %A A325636 _Antti Karttunen_, May 21 2019