OFFSET
0,3
COMMENTS
The condition that the rows be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of rows.
a(n) is the number of T_0 3-regular set multipartitions (multisets of sets) on an n-set.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..100
FORMULA
a(n) = Sum_{k=0..n} Stirling1(n,k)*A165434(k). - Andrew Howroyd, Jan 31 2020
EXAMPLE
The a(2) = 3 matrices are:
[1 0] [1 1] [1 1]
[1 0] [1 0] [1 1]
[1 0] [1 0] [1 0]
[0 1] [0 1] [0 1]
[0 1] [0 1]
[0 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 15 2020
STATUS
approved