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 A331637 Number of binary matrices with nonzero rows, a total of n ones and each column with the same number of ones. 1
 1, 4, 14, 89, 542, 5156, 47294, 570074, 7103343, 104493608, 1622632574, 28411638982, 526858348382, 10699857854372, 230297862127828, 5330284144906443, 130370767029135902, 3390229775073259800, 92801587319328411134, 2679531116538955252338 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..20. 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

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Last modified July 23 10:53 EDT 2024. Contains 374549 sequences. (Running on oeis4.)