OFFSET
1,2
COMMENTS
The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns.
FORMULA
a(n) = Sum_{d|n} A331572(n/d, d).
EXAMPLE
The a(2) = 3 matrices are:
[1 0] [1 1] [2]
[0 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 25 2020
STATUS
approved