OFFSET
1,4
COMMENTS
The condition that the rows be in decreasing order is equivalent to considering nonequivalent matrices with distinct rows up to permutation of rows.
FORMULA
a(n) = Sum_{d|n} A331039(n/d, d).
EXAMPLE
The a(6) = 6 matrices are:
[1 0 0 0 0 0] [1 1 1] [1 1 0] [1 1 0] [1 0 1] [1 1 0]
[0 1 0 0 0 0] [1 0 0] [1 0 1] [1 0 0] [1 0 0] [1 0 1]
[0 0 1 0 0 0] [0 1 0] [0 1 0] [0 1 1] [0 1 1] [0 1 1]
[0 0 0 1 0 0] [0 0 1] [0 0 1] [0 0 1] [0 1 0]
[0 0 0 0 1 0]
[0 0 0 0 0 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 24 2020
STATUS
approved