A225740 Number of arrangements of n nonattacking Queens on an n X n board, with no Queens on both main diagonals.

0, 0, 0, 2, 0, 4, 0, 12, 8, 12, 64, 760, 2080, 11524, 77672, 454376, 2972720, 19274208, 160500016, 1150812148, 9797154696, 79646705916, 771589104392

Offset: 1

Author

Vaclav Kotesovec, Aug 04 2013

Keywords

• nonn
• more
• hard

Examples

			From _Martin Ehrenstein_, Jan 10 2022: (Start)
Solutions for n=9 filtered from the Coserea link in A000170:
  3 5 8 2 9 7 1 4 6
  3 6 9 2 8 1 4 7 5
  4 6 9 3 1 8 2 5 7
  5 3 6 9 2 8 1 4 7
  5 7 4 1 8 2 9 6 3
  6 4 1 7 9 2 8 5 3
  7 4 1 8 2 9 6 3 5
  7 5 2 8 1 3 9 6 4
(End)
		

Links

• V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, p.447
• Vaclav Kotesovec, example, board 8x8, no queens on line a1-h8 and no queens on line a8-h1

Crossrefs

Cf. A000170, A003471.

Extensions

a(9)-a(19) corrected and extended with a(20)-a(23) by Martin Ehrenstein, Jan 10 2022

a(9)-a(19) confirmed by Vaclav Kotesovec, Jan 11 2022