A331637 - OEIS

A331637

Number of binary matrices with nonzero rows, a total of n ones and each column with the same number of ones.

1, 4, 14, 89, 542, 5156, 47294, 570074, 7103343, 104493608, 1622632574, 28411638982, 526858348382, 10699857854372, 230297862127828, 5330284144906443, 130370767029135902, 3390229775073259800, 92801587319328411134, 2679531116538955252338

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OFFSET

1,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..200

FORMULA

a(n) = Sum_{d|n} A262809(n/d, d).

EXAMPLE

The a(2) = 4 matrices are:

[1] [1 0] [0 1] [1 1]

[1] [0 1] [1 0]

CROSSREFS

Cf. A262809.

Sequence in context: A352289 A330465 A202139 * A340024 A190481 A316414

Adjacent sequences: A331634 A331635 A331636 * A331638 A331639 A331640

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Jan 23 2020

STATUS

approved