OFFSET
0,2
COMMENTS
The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns.
EXAMPLE
The a(1) = 4 matrices are:
[1 0 0] [1 1 0] [1 0 0] [1 1 1]
[0 1 0] [0 0 1] [0 1 1]
[0 0 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 25 2020
STATUS
approved