cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A330158 Number of nonnegative integer matrices with total sum n, distinct columns with equal sums and any number of nonzero rows in nonincreasing lexicographic order.

Original entry on oeis.org

1, 3, 4, 13, 8, 83, 16, 530, 630, 5620, 57, 119889, 102, 1901749, 1498322, 50091143, 298, 1649302673, 491, 54919254373, 16723808377, 2269075359300, 1256, 110133775311277, 26852941986, 5707320920415984, 622570195638208, 339574840900645411, 4566, 22572315004012650868
Offset: 1

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Author

Andrew Howroyd, Jan 11 2020

Keywords

Comments

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

Examples

			The a(4) = 13 matrices are:
  [1 0 0 0]  [1 0]  [1]  [1 1]  [2 0]  [1 0]  [2]
  [0 1 0 0]  [1 0]  [1]  [1 0]  [0 1]  [1 0]  [1]
  [0 0 1 0]  [0 1]  [1]  [0 1]  [0 1]  [0 2]  [1]
  [0 0 0 1]  [0 1]  [1]
.
  [2 1]  [2 0]  [1 2]  [3]  [2]  [4]
  [0 1]  [0 2]  [1 0]  [1]  [2]
		

Crossrefs

Cf. A331161.

Formula

a(n) = Sum_{d|n} A331161(n/d, d).