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 A081691 #11 Jun 16 2016 23:27:22 %S A081691 0,2,6,11,20,38,71,136,265,523,1036,2061,4110,8207,16400,32785,65554, %T A081691 131092,262165,524310,1048599,2097176,4194329,8388634,16777243, %U A081691 33554460,67108893,134217758,268435487,536870944,1073741857,2147483682 %N A081691 From P-positions in a certain game. %H A081691 A. S. Fraenkel, <a href="http://www.emis.de/journals/INTEGERS/papers/eg6/eg6.Abstract.html">New games related to old and new sequences</a>, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 4, Paper G6, 2004. %F A081691 See A081690 for formulas. %Y A081691 Apart from initial zero, complement of A081690. %K A081691 nonn %O A081691 0,2 %A A081691 _N. J. A. Sloane_, Apr 02 2003 %E A081691 More terms from _Vladeta Jovovic_, Apr 04 2003