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 A187383 #10 Apr 24 2018 08:07:34 %S A187383 0,0,0,340,3060,10320,24892,46412,75567,111492,154187,203652,259887, %T A187383 322892,392667,469212,552527,642612,739467,843092,953487,1070652, %U A187383 1194587,1325292,1462767,1607012,1758027,1915812,2080367,2251692,2429787,2614652 %N A187383 Number of 9-step S, NW and NE-moving king's tours on an n X n board summed over all starting positions. %C A187383 Row 9 of A187377. %H A187383 R. H. Hardin, <a href="/A187383/b187383.txt">Table of n, a(n) for n = 1..50</a> %F A187383 Empirical: a(n) = 3385*n^2 - 28390*n + 56892 for n>7. %F A187383 Conjectures from _Colin Barker_, Apr 24 2018: (Start) %F A187383 G.f.: x^4*(340 + 2040*x + 2160*x^2 + 2772*x^3 - 364*x^4 + 687*x^5 - 865*x^6) / (1 - x)^3. %F A187383 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>10. %F A187383 (End) %Y A187383 Cf. A187377. %K A187383 nonn %O A187383 1,4 %A A187383 _R. H. Hardin_, Mar 09 2011