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%I #33 Feb 03 2021 21:49:27
%S 1,2,21,1344,628080,2030271480,49846153939785,9350902053107858880,
%T 13807842729396124460629536,162526525004284727135887319788800,
%U 15464071313054035722739424623204673044920,12011244510939290610945342901003078567310643860160
%N 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.
%Y Cf. A005130 (Robbins numbers).
%Y 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).
%Y Cf. A172645 (case row and column sums are zero).
%K nonn
%O 1,2
%A _Eric W. Weisstein_
%E Definition corrected by Murphy Waggoner and _R. H. Hardin_, Sep 24 2013
%E a(6)-a(8) from _R. H. Hardin_, Sep 25 2013
%E a(9)-a(12) from _Andrew Howroyd_, Feb 03 2021