login
Number of nonnegative integer matrices with n distinct columns and any number of distinct nonzero rows with each column sum being 3 and rows in decreasing lexicographic order.
2

%I #8 Jan 16 2020 01:12:53

%S 1,2,15,317,12586,803764,75603729,9880078404,1719511013708,

%T 385900586669488,108870763685147631,37821200661333033093,

%U 15903952714275755480410,7978911737260660423782839,4717171385049289138016854041,3251403192784472823846341645000

%N Number of nonnegative integer matrices with n distinct columns and any number of distinct nonzero rows with each column sum being 3 and rows in decreasing lexicographic order.

%C The condition that the rows be in decreasing order is equivalent to considering nonequivalent matrices with distinct rows up to permutation of rows.

%H Andrew Howroyd, <a href="/A331344/b331344.txt">Table of n, a(n) for n = 0..100</a>

%Y Row n=3 of A331160.

%Y Cf. A331196, A331316,

%K nonn

%O 0,2

%A _Andrew Howroyd_, Jan 14 2020