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 A059421 #3 Mar 30 2012 16:49:02 %S A059421 16,136,616,2016,5376,12432,25872,49632,89232,152152,248248,390208, %T A059421 594048,879648,1271328,1798464,2496144,3405864,4576264,6063904, %U A059421 7934080,10261680,13132080,16642080,20900880,26031096,32169816,39469696 %N A059421 A diagonal of A059419. %D A059421 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 259. %K A059421 nonn,easy %O A059421 1,1 %A A059421 _N. J. A. Sloane_, Jan 30 2001 %E A059421 More terms from Larry Reeves (larryr(AT)acm.org), Feb 08 2001