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 A100920 #3 Mar 30 2012 17:29:20 %S A100920 1,5,11,19,30,43,61,77,99,120,145,172,206,233,263,302,346,386,428,477, %T A100920 517,568,631,675,744,794,863,926,989,1057,1142,1210,1275,1357,1444, %U A100920 1531,1608,1687,1782,1871,1943,2056,2140,2253,2367,2467,2596,2708,2814 %N A100920 Index of the last occurrence of n in A100798. %Y A100920 Cf. A100798, A100919. %K A100920 easy,nonn %O A100920 1,2 %A A100920 _Ray Chandler_, Dec 08 2004