A050204 - OEIS

A050204

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.

1, 2, 21, 1344, 628080, 2030271480, 49846153939785, 9350902053107858880, 13807842729396124460629536, 162526525004284727135887319788800, 15464071313054035722739424623204673044920, 12011244510939290610945342901003078567310643860160

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..12.

CROSSREFS

Cf. A005130 (Robbins numbers).

Cf. A229165 (entries in each row or column sum to 1 and there are no adjacent -1's or 1's in any row or column).

Cf. A172645 (case row and column sums are zero).

Sequence in context: A022488 A264066 A052157 * A368188 A022470 A080815

Adjacent sequences: A050201 A050202 A050203 * A050205 A050206 A050207

KEYWORD

nonn

AUTHOR

Eric W. Weisstein

EXTENSIONS

Definition corrected by Murphy Waggoner and R. H. Hardin, Sep 24 2013

a(6)-a(8) from R. H. Hardin, Sep 25 2013

a(9)-a(12) from Andrew Howroyd, Feb 03 2021

STATUS

approved