A201240 Number of ways to place 6 non-attacking wazirs on an n X n toroidal board.

0, 0, 0, 56, 7100, 252792, 3378942, 26249184, 144455454, 625745100, 2271361422, 7192874328, 20427662398, 53065637212, 127956238350, 289628321664, 620834113614, 1269178026012, 2488676915070, 4702895069400, 8598589878606, 15261688799500, 26371002575326

Offset: 1

Author

Vaclav Kotesovec, Nov 28 2011

Keywords

• nonn

Comments

Wazir is a leaper [0,1].

Links

• V. Kotesovec, Non-attacking chess pieces, 6ed, p.402

Crossrefs

Cf. A178409, A201236, A201237, A201238, A201239, A201241, A201242.

Formula

a(n) = n^2*(n^10 - 75*n^8 + 2365*n^6 - 39285*n^4 + 345034*n^2 - 1288680)/720, n>=7.

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.