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 A201240 #12 Apr 10 2020 02:15:15 %S A201240 0,0,0,56,7100,252792,3378942,26249184,144455454,625745100,2271361422, %T A201240 7192874328,20427662398,53065637212,127956238350,289628321664, %U A201240 620834113614,1269178026012,2488676915070,4702895069400,8598589878606,15261688799500,26371002575326 %N A201240 Number of ways to place 6 non-attacking wazirs on an n X n toroidal board. %C A201240 Wazir is a leaper [0,1]. %H A201240 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>, 6ed, p.402 %F A201240 a(n) = n^2*(n^10 - 75*n^8 + 2365*n^6 - 39285*n^4 + 345034*n^2 - 1288680)/720, n>=7. %F A201240 G.f.: 2*x^4 * (6*x^15 - 103*x^14 + 873*x^13 - 4241*x^12 + 12757*x^11 - 26112*x^10 + 45344*x^9 - 90774*x^8 + 189180*x^7 - 293907*x^6 + 260273*x^5 - 25077*x^4 - 315215*x^3 - 82430*x^2 - 3186*x - 28)/(x-1)^13. %Y A201240 Cf. A178409, A201236, A201237, A201238, A201239, A201241, A201242. %K A201240 nonn %O A201240 1,4 %A A201240 _Vaclav Kotesovec_, Nov 28 2011