%I #5 Feb 07 2020 20:49:28
%S 1,0,1,4,12,36,124,412,1500
%N Number of nonequivalent n-column binary matrices with 2 ones in every column and any number of distinct nonzero rows up to permutation of rows and columns.
%e The a(3) = 4 matrices are:
%e [1 1 1] [1 1 0] [1 1 1] [1 1 0]
%e [1 0 0] [1 0 1] [1 1 0] [1 0 1]
%e [0 1 0] [0 1 0] [0 0 1] [0 1 1]
%e [0 0 1] [0 0 1]
%Y Row n=2 of A331510.
%Y Cf. A331718.
%K nonn,more
%O 0,4
%A _Andrew Howroyd_, Feb 02 2020