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 A004156 #13 Apr 05 2014 01:37:01 %S A004156 1,3,5,7,9,11,31,51,71,91,12,32,52,72,92,13,33,53,73,93,14,34,54,74, %T A004156 94,15,35,55,75,95,16,36,56,76,96,17,37,57,77,97,18,38,58,78,98,19,39, %U A004156 59,79,99,101,301,501,701,901,111,311,511,711,911,121,321,521 %N A004156 Odd numbers written backwards. %F A004156 a(n) = A004086(A005408(n)). - _Michel Marcus_, Apr 05 2014 %Y A004156 Cf. A005408. %K A004156 nonn,base %O A004156 0,2 %A A004156 _N. J. A. Sloane_ %E A004156 More terms from _Eric M. Schmidt_, Apr 04 2014