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 A171955 #3 Mar 30 2012 16:51:56 %S A171955 12,16,19,34,37,39,54,91,112,123,136,175,253,286,295,318,322,355,378, %T A171955 386,408,413,414,526,543,555,572,620,669,737,759,768,818,865,874,895, %U A171955 900,901,926,942,947,948,956,1043,1086,1148,1170,1175,1176 %N A171955 Positions of 5's in A181391. %H A171955 N. J. A. Sloane, <a href="/A171955/b171955.txt">Table of n, a(n) for n = 1..4802</a> %Y A171955 Cf. A181391, A171865, A171951-A171956. %K A171955 nonn %O A171955 1,1 %A A171955 _N. J. A. Sloane_, Oct 29 2010