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 A280491 #6 Jan 10 2017 19:12:27 %S A280491 1,2,1,1,1,6,1,1,9,2,1,2,1,2,3,1,1,3,1,20,3,2,1,2,1,2,1,4,1,30,1,1,3, %T A280491 2,1,3,1,2,3,4,1,6,1,4,5,2,1,2,1,5,3,4,1,1,1,56,3,2,1,6,1,2,1,1,1,6,1, %U A280491 4,3,10,1,3,1,2,75,4,1,6,1,4,1,2,1,84,1,2,3,8,1,10,1,4,3,2,1,2,1,1,1,1,1,6,1,8,15,2,1,1,1,10,3,8,1,6,1,4,1,2 %N A280491 a(n) = gcd(n,A122111(n)). %H A280491 Antti Karttunen, <a href="/A280491/b280491.txt">Table of n, a(n) for n = 1..8192</a> %F A280491 a(n) = gcd(n,A122111(n)). %F A280491 a(n) = n / A280490(n). %F A280491 Other identities. For all n >= 1: %F A280491 a(A122111(n)) = a(n). %o A280491 (Scheme) (definec (A280491 n) (gcd n (A122111 n))) %Y A280491 Cf. A122111, A280490, also A280489. %Y A280491 Cf. A088902 (the fixed points, n for which a(n) = n). %K A280491 nonn %O A280491 1,2 %A A280491 _Antti Karttunen_, Jan 09 2017