A201236 Number of ways to place 2 non-attacking wazirs on an n X n toroidal board.

0, 2, 18, 88, 250, 558, 1078, 1888, 3078, 4750, 7018, 10008, 13858, 18718, 24750, 32128, 41038, 51678, 64258, 79000, 96138, 115918, 138598, 164448, 193750, 226798, 263898, 305368, 351538, 402750, 459358, 521728, 590238, 665278, 747250, 836568, 933658, 1038958

Offset

1,2

Comments

A wazir is a leaper [0,1].

Links

Table of n, a(n) for n=1..38.

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

Formula

a(n) = n^2*(n^2-5)/2, n>=3.

G.f.: 2*x^2 * (2*x^5 - 9*x^4 + 15*x^3 - 9*x^2 - 4*x - 1)/(x-1)^5.

Crossrefs

Cf. A172225, A201237, A201238, A201239, A201240, A201241, A201242.

Sequence in context: A070171 A357757 A172529 * A206623 A036800 A157052

Adjacent sequences: A201233 A201234 A201235 * A201237 A201238 A201239

Keyword

nonn

Author

Vaclav Kotesovec, Nov 28 2011

Status

approved