A321511 Number of alternating sign n X n matrices excluding permutation matrices.

0, 0, 0, 1, 18, 309, 6716, 213308, 10809896, 911472580, 129530643900, 31095704935575, 12611311380675900, 8639383512070631700, 9995541355360989190800, 19529076234659969430529200, 64427185703425668434106855840, 358869201916137601091798728321296

Offset

0,5

Links

Michael De Vlieger, Table of n, a(n) for n = 0..93

Paul Barry, Centered polygon numbers, heptagons and nonagons, and the Robbins numbers, arXiv:2104.01644 [math.CO], 2021.

Formula

a(n) = A005130(n) - n!

Mathematica

a[n_] := Product[(3 k + 1)!/(n + k)!, {k, 0, n-1}] - n!; a /@ Range[0, 17] (* Giovanni Resta, Nov 20 2018 *)

Crossrefs

Cf. A005130.

Sequence in context: A179121 A226298 A368537 * A208537 A292299 A158532

Adjacent sequences: A321508 A321509 A321510 * A321512 A321513 A321514

Keyword

nonn

Author

Wendy Appleby, Nov 11 2018

Status

approved