A189875 Number of ways to place n nonattacking composite pieces queen + rider[1,5] on an n X n chessboard.

1, 0, 0, 2, 10, 0, 0, 0, 40, 52, 152, 260, 1192, 4144, 18408, 71552, 312936, 1498156, 7854672, 44923706, 213840604, 1156549592

Offset

1,4

Comments

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

Links

Table of n, a(n) for n=1..22.

Vaclav Kotesovec, Non-attacking chess pieces, 6ed, 2013, p. 678.

Wikipedia, Fairy chess piece

Crossrefs

Cf. A102388, A189873, A189874, A189852.

Sequence in context: A181500 A189876 A189867 * A189866 A364253 A189874

Adjacent sequences: A189872 A189873 A189874 * A189876 A189877 A189878

Keyword

nonn,hard,changed

Author

Vaclav Kotesovec, Apr 29 2011

Status

approved