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A331649
Number of binary matrices with n distinct columns and any number of distinct nonzero rows with 2 ones in every column and columns in decreasing lexicographic order.
2
1, 0, 3, 17, 230, 3264, 60338, 1287062, 31900620, 893284155, 27972470286, 967596779631, 36654913572018, 1509052435744560, 67089897326522970, 3203343744126663616, 163486870943294124046, 8881542959996746368420, 511713241494851800728865, 31165957861936237845310435
OFFSET
0,3
COMMENTS
The condition that the columns be in decreasing order is equivalent to considering nonequivalent matrices with distinct columns up to permutation of columns.
LINKS
EXAMPLE
The a(2) = 3 matrices are:
[1 1] [1 0] [1 0]
[1 0] [1 1] [0 1]
[0 1] [0 1] [1 1]
CROSSREFS
Row n=2 of A331569.
Sequence in context: A194925 A072350 A181032 * A322737 A376008 A201107
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 24 2020
STATUS
approved