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 A280489 #6 Jan 10 2017 19:12:04 %S A280489 1,2,1,1,1,3,1,1,3,1,1,1,1,1,3,1,1,3,1,5,3,1,1,1,1,1,1,1,1,15,1,1,3,1, %T A280489 1,1,1,1,3,1,1,3,1,1,5,1,1,1,1,5,3,1,1,3,1,7,3,1,1,5,1,1,1,1,1,3,1,1, %U A280489 3,5,1,1,1,1,15,1,1,3,1,1,1,1,1,7,1,1,3,1,1,3,1,1,3,1,1,1,1,1,1,25,1,3,1,1,15,1,1,1,1,5,3,1,1,3,1,1,1,1,1 %N A280489 a(n) = gcd(n,A241909(n)). %H A280489 Antti Karttunen, <a href="/A280489/b280489.txt">Table of n, a(n) for n = 1..8192</a> %F A280489 a(n) = gcd(n,A241909(n)). %F A280489 a(n) = n / A280488(n). %F A280489 Other identities. For all n >= 1: %F A280489 a(A241909(n)) = a(n). %o A280489 (Scheme) (define (A280489 n) (gcd n (A241909 n))) %Y A280489 Cf. A241909, A280488, A280491. %K A280489 nonn %O A280489 1,2 %A A280489 _Antti Karttunen_, Jan 09 2017