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 A186854 #14 Jan 07 2023 15:15:20 %S A186854 16,400,2800,9328,21480,39616,63440,92656,127264,167264,212656,263440, %T A186854 319616,381184,448144,520496,598240,681376,769904,863824,963136, %U A186854 1067840,1177936,1293424,1414304,1540576,1672240,1809296,1951744,2099584,2252816,2411440 %N A186854 Number of 5-step knight's tours on an (n+2) X (n+2) board summed over all starting positions. %H A186854 Andrew Howroyd, <a href="/A186854/b186854.txt">Table of n, a(n) for n = 1..1000</a> %F A186854 Empirical: a(n) = 2696*n^2 - 11224*n + 9904 for n > 5. %F A186854 The above empirical formula is correct. See A186851 for details. - _Andrew Howroyd_, Jan 07 2023 %e A186854 Some solutions for 5 X 5: %e A186854 0 0 0 0 1 0 2 0 0 0 0 5 0 0 0 0 1 0 0 0 %e A186854 0 3 0 0 0 0 0 0 3 0 0 0 0 2 0 3 0 0 0 0 %e A186854 0 0 0 2 0 1 0 0 0 0 4 0 0 0 0 0 0 2 5 0 %e A186854 0 0 4 0 0 0 0 4 0 0 0 0 3 0 1 0 4 0 0 0 %e A186854 0 0 0 0 5 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 %o A186854 (PARI) row(5, 30) \\ row(m, n) defined in A186851. - _Andrew Howroyd_, Jan 07 2023 %Y A186854 Row 5 of A186851. %K A186854 nonn %O A186854 1,1 %A A186854 _R. H. Hardin_, Feb 27 2011 %E A186854 Terms a(25) and beyond from _Andrew Howroyd_, Jan 07 2023