OFFSET
1,2
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
Andrew Howroyd, Table of n, a(n) for n = 1..200
FORMULA
a(n) = Sum_{d|n} A331278(n/d, d).
a(p) = 2^(p-1) + 1 for prime p.
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 15 2020
STATUS
approved