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 A125997 #4 Mar 31 2012 13:21:13
%S A125997 9,25,73,89,521,537,585,601,2057,2073,2121,2137,2569,2585,2633,2649,
%T A125997 4105,4121,4169,4185,4617,4633,4681,4697,6153,6169,6217,6233,6665,
%U A125997 6681,6729,6745,8201,8217,8265,8281,8713,8729,8777,8793,10249,10265
%N A125997 A106486-encodings of combinatorial games equivalent to game {0|1}.
%C A125997 These are codes for games which belong to the same equivalence class as the game {0|1} (game 1/2).
%H A125997 A. Karttunen, <a href="/A126000/a126000.scm.txt">Scheme-program for computing this sequence.</a>
%e A125997 Game {0|1} is encoded as 2^(2*0) + 2^(1+2*1) = 9, thus 9 is the first term of this sequence. Also 25 (= 2^(2*2) + 2^(2*0) + 2^(1+2*1)) belongs into this sequence, as it encodes game {-1,0|1}, where, as the option -1 is dominated by option 0, the former can be deleted, resulting the same game {0|1}.
%Y A125997 Row 7 of A126000.
%K A125997 nonn
%O A125997 1,1
%A A125997 _Antti Karttunen_, Dec 18 2006