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%I #9 May 17 2020 01:40:57
%S 1,1,3,19,391,25428,5422820,3868544673,9374373474455,
%T 78121590505558308,2262375741577763676620,229653423345084153764141412,
%U 82310438395814327559991274396712,104810153877236566878585186368604425875
%N Number of lower triangles of an n X n 0..4 array with all row sums equal to the length of the row and all column sums equal to the length of the column.
%e Some solutions for n=4:
%e ..1........1........1........1........1........1........1........1
%e ..2.0......0.2......1.1......0.2......0.2......0.2......1.1......2.0
%e ..1.0.2....1.0.2....1.0.2....1.0.2....3.0.0....3.0.0....1.0.2....1.0.2
%e ..0.3.0.1..2.1.0.1..1.2.0.1..2.1.0.1..0.1.2.1..0.1.2.1..1.2.0.1..0.3.0.1
%Y Column 4 of A195644.
%K nonn
%O 1,3
%A _R. H. Hardin_, Sep 21 2011
%E a(12)-a(14) from _Andrew Howroyd_, May 16 2020