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 A133719 #7 Sep 13 2015 21:06:12 %S A133719 1,22,226,1371,5901,20097,57813,146427,335742,710677,1408693,2643004, %T A133719 4732728,8141238,13524078,21787914,34162095,52284504,78303484, %U A133719 114997729,165916135,235539711,329467755,454630605,619531380,834519231 %N A133719 Column 4 of array in A133713. %p A133719 A133719 := proc(l) %p A133719 A133713(l,4) ; %p A133719 end proc: %p A133719 seq(A133719(l),l=2..30) ; # _R. J. Mathar_, Nov 23 2011 %K A133719 nonn %O A133719 2,2 %A A133719 _N. J. A. Sloane_, Dec 30 2007