

A137432


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


24



4, 32, 344, 4460, 66532, 1118398, 20984924, 437500380, 10105541204, 257860425672, 7241521734020, 222770819826574, 7466859257161488, 271156951835070930, 10609740515840572076, 444982726973034212924, 19911203110764903275188, 946564783226311159219150
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OFFSET

1,1


LINKS

Alex V. Breger, Table of n, a(n) for n = 1..31
V. Kotesovec, Number of ways of placing nonattacking queens, kings, bishops and knights
Artem M. Karavaev, Zealint blog (in Russian)


FORMULA

Conjecture: limit of a(n+1)/(n*a(n)) as n>infinity is e.


CROSSREFS

Cf. A018807, A173033.
Sequence in context: A123309 A186391 A231446 * A177750 A304911 A224993
Adjacent sequences: A137429 A137430 A137431 * A137433 A137434 A137435


KEYWORD

nonn,nice,hard


AUTHOR

Vaclav Kotesovec, Aug 31 2011


EXTENSIONS

a(11)a(12) from Vaclav Kotesovec, Sep 08 2011
a(13)a(27) from Alex V. Breger, Sep 10 2011
a(28)a(31) from Alex V. Breger, Sep 12 2011


STATUS

approved



