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A321511
Number of alternating sign n X n matrices excluding permutation matrices.
1
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
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
KEYWORD
nonn
AUTHOR
Wendy Appleby, Nov 11 2018
STATUS
approved