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 A331705 Number of nonnegative integer matrices with n distinct columns and any number of distinct nonzero rows with column sums 3 and columns in decreasing lexicographic order. 3

%I

%S 1,3,42,1900,184550,29724388,7137090958,2393644524156,

%T 1068870144819960,613045196870306340,439190550399403297437,

%U 384354189217232125992320,403475262029493557613389128,500401167055816780694578266750,723870101627745660876118985228250

%N Number of nonnegative integer matrices with n distinct columns and any number of distinct nonzero rows with column sums 3 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.

%H Andrew Howroyd, <a href="/A331705/b331705.txt">Table of n, a(n) for n = 0..100</a>

%F a(n) = (1/n!)*Sum_{k=0..n} abs(Stirling1(n, k)) * A331645(k).

%e The a(1) = 3 matrices are:

%e [2] [1] [3]

%e [1] [2]

%Y Row n=3 of A331570.

%Y Cf. A331645, A331704.

%K nonn

%O 0,2

%A _Andrew Howroyd_, Jan 25 2020

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Last modified November 29 18:41 EST 2021. Contains 349416 sequences. (Running on oeis4.)