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 A331638 Number of binary matrices with nonzero rows, a total of n ones and each column with the same number of ones and columns in nonincreasing lexicographic order. 2
 1, 3, 5, 16, 17, 140, 65, 1395, 2969, 22176, 1025, 1050766, 4097, 13010328, 128268897, 637598438, 65537, 64864962683, 262145, 1676258452736, 28683380484257, 24908619669860, 4194305, 30567710172480050, 8756434134071649, 62128557507554504, 21271147396968151093 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns. LINKS Table of n, a(n) for n=1..27. FORMULA a(n) = Sum_{d|n} A330942(n/d, d). a(p) = 2^(p-1) + 1 for prime p. CROSSREFS Cf. A330942, A331639. Sequence in context: A006593 A115724 A039782 * A080056 A330055 A019096 Adjacent sequences: A331635 A331636 A331637 * A331639 A331640 A331641 KEYWORD nonn AUTHOR Andrew Howroyd, Jan 23 2020 STATUS approved

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Last modified August 5 14:58 EDT 2024. Contains 374950 sequences. (Running on oeis4.)