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 A274304 #3 Jun 20 2016 13:23:14 %S A274304 1,4,192,23040,5160960,1857945600,980995276800,714164561510400, %T A274304 685597979049984000,839171926357180416000,1275541328062914232320000, %U A274304 2357200374260265501327360000,5204698426366666226930810880000,13532215908553332190020108288000000 %N A274304 A bisection of A002866. %Y A274304 Cf. A002671, A002866. %K A274304 nonn %O A274304 0,2 %A A274304 _N. J. A. Sloane_, Jun 20 2016