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 A119019 #5 Mar 31 2012 13:21:31 %S A119019 1,0,2,9,4,50,3,266,6,12,5,33,8,286,7,10,16,204,14,342,15,21,18,483, %T A119019 20,55,24,36,22,754,25,1767,26,11,17,56,27,666,19,13,28,861,30,3741, %U A119019 32,35,23,611,38,406,42,39,44,3233,40,66,46,76,29,4307,45 %N A119019 Index of occurrence of n in A119018, or 0 if n is not present in A119018. %Y A119019 Cf. A119018. %K A119019 nonn %O A119019 0,3 %A A119019 _Franklin T. Adams-Watters_, May 08 2006 %E A119019 More terms from _R. J. Mathar_, Sep 07 2007