OFFSET
1,2
COMMENTS
a(n) is the number of symmetric nonnegative integer matrices with sum of entries equal to n, no zero rows or columns, and weakly decreasing row and column sums. - Ludovic Schwob, Aug 29 2023
LINKS
Ludovic Schwob, Table of n, a(n) for n = 1..39
E. Egge et al., From quasisymmetric expansions to Schur expansions via a modified inverse Kostka matrix
E. Egge et al., From quasisymmetric expansions to Schur expansions via a modified inverse Kostka matrix, European Journal of Combinatorics, Volume 31, Issue 8, December 2010, Pages 2014-2027.
Wouter Meeussen, Schur Polynomials
Wouter Meeussen, Kostka numbers up to partitions of 20
Wouter Meeussen, Mathematica code for 'kostka' function
EXAMPLE
For n=4, {1,1,1,1,1} + {0,1,1,2,3} + {0,0,1,1,2} + {0,0,0,1,3} + {0,0,0,0,1} = 21.
MATHEMATICA
See Meeussen link.
CROSSREFS
KEYWORD
nonn
AUTHOR
Wouter Meeussen, Dec 26 2010
EXTENSIONS
a(21) onwards from Ludovic Schwob, Feb 22 2023
STATUS
approved