

A194648


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


3



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



