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 A331710 Number of nonnegative integer matrices with n columns and any number of distinct nonzero rows with column sums 3 and columns in nonincreasing lexicographic order. 3

%I

%S 1,3,45,1987,190379,30474159,7287577611,2436916655479,

%T 1085776582252197,621663581843731535,444746638465623906738,

%U 388773810523972862494769,407727415097448880517583006,505268334502886263575349570013,730406898110019766652845079212010

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

%C The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns.

%H Andrew Howroyd, <a href="/A331710/b331710.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 A331572.

%Y Cf. A331645, A331709.

%K nonn

%O 0,2

%A _Andrew Howroyd_, Jan 25 2020

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Last modified November 29 04:22 EST 2021. Contains 349416 sequences. (Running on oeis4.)