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 A265900 #7 Jan 17 2016 14:01:03 %S A265900 1,7,27,62,227,496,1013,2045,7893,16226,32650,65414,131026,262109, %T A265900 524267,1048572 %N A265900 Main diagonal of arrays A265901 and A265903. %F A265900 a(n) = A265901(n,n) = A265903(n,n). %o A265900 (Scheme) (define (A265900 n) (A265901bi n n)) ;; Code for A265901bi given in A265901. %Y A265900 Cf. A265901, A265903, A265909. %K A265900 nonn,more %O A265900 1,2 %A A265900 _Antti Karttunen_, Jan 09 2016