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A201241
Number of ways to place 7 non-attacking wazirs on an n X n toroidal board.
8
0, 0, 0, 16, 4450, 442980, 11281312, 139580160, 1103589198, 6433276500, 30047250222, 118507673088, 408912072478, 1265701033492, 3579712962750, 9380986518528, 23027843919870, 53409035159316, 117860600410206, 248890790976000, 505371757001454, 990655558290772
OFFSET
1,4
COMMENTS
Wazir is a leaper [0,1].
FORMULA
a(n) = n^2*(n^12 - 105*n^10 + 4795*n^8 - 122115*n^6 + 1834084*n^4 - 15461460*n^2 + 57441600)/5040, n>=8.
G.f.: -2*x^4 * (7*x^18 - 177*x^17 + 1965*x^16 - 12491*x^15 + 53736*x^14 - 175854*x^13 + 461641*x^12 - 942615*x^11 + 1320318*x^10 - 788656*x^9 - 1206129*x^8 + 3443471*x^7 - 3128600*x^6 - 552570*x^5 + 7435235*x^4 + 2548291*x^3 + 188955*x^2 + 2105*x + 8)/((x-1)^15).
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Nov 28 2011
STATUS
approved