A195653 Number of ways to place 9n nonattacking kings on an 18 X 2n cylindrical chessboard.

5120, 21508, 109796, 626780, 3877300, 25603228, 178909300, 1314748124, 10105541204, 80812754568, 668845118276, 5700499630916, 49800720887968, 444140848321356, 4029482453905756, 37080781799409148, 345278411878468044, 3246772078088155432, 30781946900321278256

Offset

1,1

Comments

This cylinder is horizontal: a chessboard where it is supposed that rows 1 and 2n are in contact (number of columns = 18, number of rows = 2n).

Links

Alex V. Breger, Table of n, a(n) for n = 1..1000

Artem M. Karavaev, Zealint blog (in Russian)

V. Kotesovec, Non-attacking chess pieces

Vaclav Kotesovec, Generating function

Index entries for linear recurrences with constant coefficients, order 400.

Formula

Recurrence order is 400.

Crossrefs

Cf. A137432, A195648, A195658.

Sequence in context: A215839 A258729 A259425 * A187030 A237328 A186968

Adjacent sequences: A195650 A195651 A195652 * A195654 A195655 A195656

Keyword

nonn

Author

Vaclav Kotesovec, Sep 22 2011

Status

approved