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 A260970 #6 Aug 11 2015 12:15:28 %S A260970 1,4,18,176,11363 %N A260970 Number of hereditarily transitive normal play partisan games born on or before day n. %C A260970 A game is transitive if any position reached by any number of consecutive moves by one player can be reached in a single move by that player. It is hereditarily transitive if it and all its followers are transitive. %C A260970 The hereditarily transitive games born by day n form a distributive lattice whose Hasse diagram is planar. It is conjectured (known for n<=3) that the number of antichains in this lattice is 2^A000372(n)-2. %C A260970 Aaron Siegel attributes the values up to a(3) to Angela Siegel, and a(4) to Neil McKay. %D A260970 Aaron N. Siegel, Combinatorial Game Theory, AMS Graduate Texts in Mathematics Vol 146 (2013), p. 158. %Y A260970 Cf. A065401 (all games), also A000372 for antichain conjecture. %K A260970 nonn,more %O A260970 0,2 %A A260970 _Christopher E. Thompson_, Aug 07 2015