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%I #7 Jun 24 2023 18:14:57
%S 2,10,138,5314,575122,176041978,153143689594,380082566144530,
%T 2699632942815871042,55016905649245690586122,
%U 3223966155402204759824471786
%N Number of n X n 0..1 matrices with row and column i=1..n having sum <= i.
%e Some solutions for n=4
%e ..0..1..0..0....1..0..0..0....1..0..0..0....1..0..0..0....1..0..0..0
%e ..0..0..1..1....0..1..1..0....0..1..0..0....0..1..0..0....0..0..0..0
%e ..1..0..0..1....0..1..0..1....0..0..1..1....0..1..1..0....0..1..1..1
%e ..0..1..1..1....0..0..1..0....0..1..0..0....0..0..1..1....0..0..1..1
%Y Column 1 of A213962.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jun 28 2012