A194648 Number of ways to place 6n nonattacking kings on a 12 X 2n cylindrical chessboard.

448, 1732, 7918, 39316, 205628, 1118398, 6286658, 36383284, 216134044, 1314160492, 8155899320, 51526819510, 330559583178, 2148524237842, 14120142260138, 93669254201140, 626289974615094, 4215364545901036, 28531464984810918, 194028126730583796

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 = 12, number of rows = 2n).

Links

Table of n, a(n) for n=1..20.

V. Kotesovec, Number of ways of placing non-attacking queens, kings, bishops and knights

Vaclav Kotesovec, G.f., recurrence and explicit formula

Formula

Asymptotic: a(n) ~ 2*7^n.

Crossrefs

Cf. A174154, A194644, A194645, A194646, A194647, A137432, A195594.

Sequence in context: A251646 A235177 A346514 * A348344 A234438 A048632

Adjacent sequences: A194645 A194646 A194647 * A194649 A194650 A194651

Keyword

nonn

Author

Vaclav Kotesovec, Aug 31 2011

Status

approved