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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

%I #5 Jan 23 2020 16:48:55

%S 1,3,5,16,17,140,65,1395,2969,22176,1025,1050766,4097,13010328,

%T 128268897,637598438,65537,64864962683,262145,1676258452736,

%U 28683380484257,24908619669860,4194305,30567710172480050,8756434134071649,62128557507554504,21271147396968151093

%N 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.

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

%F a(n) = Sum_{d|n} A330942(n/d, d).

%F a(p) = 2^(p-1) + 1 for prime p.

%Y Cf. A330942, A331639.

%K nonn

%O 1,2

%A _Andrew Howroyd_, Jan 23 2020

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