A333902 Number of nonequivalent 3 X n nonnegative integer matrices with all column sums 3 and row sums n up to permutation of rows.

1, 1, 2, 10, 70, 566, 4781, 41357, 364470, 3257830, 29450557, 268701797, 2470513849, 22862694505, 212758007450, 1989477010250, 18682005254390, 176085344355510, 1665167298000005, 15793406377949405, 150192477267201945, 1431741484334863145, 13678227386467491410

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: A166076 A354307 A217938 * A051405 A005568 A036075

Adjacent sequences: A333899 A333900 A333901 * A333903 A333904 A333905

Keyword

nonn

Author

Andrew Howroyd, Apr 18 2020

Status

approved