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 A115229 #5 Mar 31 2012 20:35:52 %S A115229 3,12,16,31,21,44,3,6 %N A115229 Number of ways in chess to force mate in n moves for a single knight against a single pawn, without duals, without short mates and excluding rotations, mirroring and color reversing. %C A115229 The mate is only possible against a pawn on a border line (a-line or h-line). %C A115229 No non-dual (single solution) mates are possible beyond n = 7 (cf. Springerzauber, page 178). %C A115229 Obviously the positions with the higher number of moves lead via a unique chain of positions with the lower numbers. %D A115229 John Selman and Harrie Grondijs, Springerzauber, 1998, chapter 16. %e A115229 Example: The three positions with 0 moves (checkmate) are: %e A115229 a) White: Kc2, Nb3, Black: Ka1, Pawn a2 %e A115229 b) White: Kc1, Nb3, Black: Ka1, Pawn a2 %e A115229 c) White: Kc1, Nc2, Black: Ka1, pawn a2 %K A115229 nonn %O A115229 0,1 %A A115229 _N. J. A. Sloane_, based on email from _Harrie Grondijs_, Mar 06 2006