A190393 Number of ways to place n nonattacking nightriders on an n X n toroidal board.

1, 2, 6, 24, 120, 144, 28, 1408, 2025, 86400, 1782, 1092096, 4186, 31360, 241920000, 23953408, 140692, 114108912, 1092690

Offset

1,2

Comments

A nightrider is a fairy chess piece that can move (proportionate to how a knight moves) in any direction.

Links

Table of n, a(n) for n=1..19.

Vaclav Kotesovec, Non-attacking chess pieces, 6ed, 2013, p. 338.

Crossrefs

Cf. A172141, A173429, A051906.

Sequence in context: A340515 A308819 A319206 * A263709 A279435 A263699

Adjacent sequences: A190390 A190391 A190392 * A190394 A190395 A190396

Keyword

nonn,nice,hard,more,changed

Author

Vaclav Kotesovec, May 10 2011

Extensions

Terms a(16)-a(17) from Vaclav Kotesovec, May 14 2011

Terms a(18)-a(19) from Vaclav Kotesovec, May 28 2011

Status

approved