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 A171951 #3 Mar 30 2012 16:51:56 %S A171951 3,9,51,97,133,146,160,172,191,206,240,261,273,313,342,362,396,415, %T A171951 440,470,483,502,516,536,565,593,615,640,660,677,693,724,750,784,796, %U A171951 807,832,853,902,949,963,985,1009,1038,1052,1073,1095,1113,1177 %N A171951 Positions of 1's in A181391. %H A171951 N. J. A. Sloane, <a href="/A171951/b171951.txt">Table of n, a(n) for n = 1..2762</a> %Y A171951 Cf. A181391, A171865, A171951-A171956. %K A171951 nonn %O A171951 1,1 %A A171951 _N. J. A. Sloane_, Oct 29 2010