A189859 Number of ways to place n nonattacking composite pieces rook + rider[3,5] on an n X n chessboard.

1, 2, 6, 24, 120, 464, 2274, 13236, 91760, 740562, 5305548, 43237840, 395858894, 4087066620, 46633569480, 509698057110

Offset

1,2

Comments

a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+3k)-p(i)|<>5k AND |p(j+5k)-p(j)|<>3k for all i>=1, j>=1, k>=1, i+3k<=n, j+5k<=n

Links

Table of n, a(n) for n=1..16.

V. Kotesovec, Number of ways of placing non-attacking queens, kings, bishops and knights (in English and Czech)

Wikipedia, Fairy chess piece

Crossrefs

Cf. A000170, A189852, A189856

Sequence in context: A062348 A189856 A189567 * A189569 A174701 A178848

Adjacent sequences: A189856 A189857 A189858 * A189860 A189861 A189862

Keyword

nonn,hard

Author

Vaclav Kotesovec, Apr 29 2011

Status

approved