# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a331638
Showing 1-1 of 1

%I A331638 #5 Jan 23 2020 16:48:55
%S A331638 1,3,5,16,17,140,65,1395,2969,22176,1025,1050766,4097,13010328,
%T A331638 128268897,637598438,65537,64864962683,262145,1676258452736,
%U A331638 28683380484257,24908619669860,4194305,30567710172480050,8756434134071649,62128557507554504,21271147396968151093
%N 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.
%C A331638 The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns.
%F A331638 a(n) = Sum_{d|n} A330942(n/d, d).
%F A331638 a(p) = 2^(p-1) + 1 for prime p.
%Y A331638 Cf. A330942, A331639.
%K A331638 nonn
%O A331638 1,2
%A A331638 _Andrew Howroyd_, Jan 23 2020

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE