Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #4 Jan 25 2020 20:55:12
%S 0,1,46,1900,73028,2448599,75497242,2339274204,69674762468,
%T 1979828352817,54476556180342,1451352388018928,37417987990316376,
%U 936855054326483475,22833066202591181758,542259452432969505704,12569324678536063256324,284784345516356806067001,6313245421002223574950650
%N Number of nonnegative integer matrices with 3 distinct columns and any number of distinct nonzero rows with column sums n and columns in decreasing lexicographic order.
%C The condition that the columns be in decreasing order is equivalent to considering nonequivalent matrices with distinct columns up to permutation of columns.
%e The a(1) = 1 matrix is:
%e [1 0 0]
%e [0 1 0]
%e [0 0 1]
%Y Column k=3 of A331570.
%Y Cf. A331706.
%K nonn
%O 0,3
%A _Andrew Howroyd_, Jan 25 2020