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 A270813 #7 Apr 10 2016 10:48:24 %S A270813 2,3,5,6,8,9,10,11,17,13,21,21,24,26,22,17,30,37,50,23,16,53,55,12,61 %N A270813 First differences of A003022. %C A270813 Surprisingly irregular. %Y A270813 Cf. A003022. %K A270813 nonn,hard,more %O A270813 2,1 %A A270813 _N. J. A. Sloane_, Apr 08 2016