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A333902 Number of nonequivalent 3 X n nonnegative integer matrices with all column sums 3 and row sums n up to permutation of rows. 2
1, 1, 2, 10, 70, 566, 4781, 41357, 364470, 3257830, 29450557, 268701797, 2470513849, 22862694505, 212758007450, 1989477010250, 18682005254390, 176085344355510, 1665167298000005, 15793406377949405, 150192477267201945, 1431741484334863145, 13678227386467491410 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Number of factorizations of m^3 into 3 factors, where m is a product of exactly n distinct primes and each factor is a product of n primes (counted with multiplicity).

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..100

EXAMPLE

The a(2) = 2 matrices are:

  [1 1]  [0 2]

  [1 1]  [1 1]

  [1 1]  [2 0]

CROSSREFS

Row n=3 of A257462.

Sequence in context: A121201 A166076 A217938 * A051405 A005568 A036075

Adjacent sequences:  A333899 A333900 A333901 * A333903 A333904 A333905

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Apr 18 2020

STATUS

approved

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Last modified September 20 10:24 EDT 2020. Contains 337264 sequences. (Running on oeis4.)