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A229165 a(n) is the number of n X n matrices of 0's, 1's and -1's in which the entries in each row or column sum to 1 and there are no adjacent -1's or 1's in any row or column. 1
1, 2, 7, 104, 7255, 2280064, 2708080414, 13039886441460 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..8.

CROSSREFS

Cf. A005130 (Robbins numbers).

Cf. A050204 (entries in each row or column sum to 1).

Sequence in context: A206157 A102747 A122524 * A307329 A162634 A235470

Adjacent sequences:  A229162 A229163 A229164 * A229166 A229167 A229168

KEYWORD

nonn,more

AUTHOR

Eric W. Weisstein, Sep 25 2013

EXTENSIONS

Additional terms from R. H. Hardin, Sep 25 2013

STATUS

approved

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Last modified October 17 08:36 EDT 2019. Contains 328107 sequences. (Running on oeis4.)