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 A187048 #8 Jul 22 2025 10:39:12 %S A187048 0,0,24,272,1084,2660,5032,8164,12056,16708,22120,28292,35224,42916, %T A187048 51368,60580,70552,81284,92776,105028,118040,131812,146344,161636, %U A187048 177688,194500,212072,230404,249496,269348,289960,311332,333464,356356,380008 %N A187048 Number of 4-step one or two space at a time bishop's tours on an n X n board summed over all starting positions. %C A187048 Row 4 of A187046 %F A187048 Empirical: a(n) = 380*n^2 - 2568*n + 4388 for n>5 %e A187048 Some solutions for 4X4 %e A187048 ..0..0..4..0....0..0..0..0....0..0..1..0....0..0..3..0....0..1..0..0 %e A187048 ..0..0..0..3....4..0..1..0....0..3..0..0....0..2..0..0....0..0..3..0 %e A187048 ..0..0..2..0....0..0..0..2....2..0..0..0....4..0..0..0....0..0..0..2 %e A187048 ..0..0..0..1....0..0..3..0....0..0..0..4....0..0..0..1....4..0..0..0 %K A187048 nonn %O A187048 1,3 %A A187048 _R. H. Hardin_ Mar 02 2011