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 A136248 #4 Mar 30 2012 18:34:49 %S A136248 1,1,1,1,1,1,3,4,6,4,3,1,1,7,13,26,31,31,25,13,6,1,1,15,40,100,171, %T A136248 220,255,215,156,85,35,10,1 %N A136248 Triangle H4 read by rows: see link for definition. %C A136248 Row n has 3n+1 terms. %H A136248 Gottfried Helms, <a href="/A136206/a136206.txt">Comments on A136206 and A136248</a> %e A136248 Triangle begins: %e A136248 1 %e A136248 1 1 1 1 %e A136248 1 3 4 6 4 3 1 %e A136248 1 7 13 26 31 31 25 13 6 1 %e A136248 1 15 40 100 171 220 255 215 156 85 35 10 1 %K A136248 nonn,tabf %O A136248 1,7 %A A136248 _Gottfried Helms_, Apr 16 2008