OFFSET
0,3
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..100
E. A. Bender, Partitions of multisets, Discrete Mathematics 9 (1974) 301-312.
J. S. Devitt and D. M. Jackson, The enumeration of covers of a finite set, J. London Math. Soc.(2) 25 (1982), 1-6.
Doron Zeilberger, In How Many Ways Can You Reassemble Several Russian Dolls?, has links to more terms and related sequences
Doron Zeilberger, In How Many Ways Can You Reassemble Several Russian Dolls?, arXiv:0909.3453 [math.CO], 2009.
Doron Zeilberger, BABUSHKAS; Local copy
EXAMPLE
For n=2, a(2)=4, since if you have two sets of identical triples the A-brothers and the B-sisters, and you want to arrange them into a multiset of nonempty sets, where no one is allowed to cohabitate with his or her sibling, the following are possible 1.{{AB},{AB},{AB}} 2.{{AB},{AB},{A},{B}} 3.{{AB},{A},{A},{B},{B}} 4.{{A},{A},{A},{B},{B},{B}}.
MAPLE
Do SeqBrn(3, n); in the Maple package BABUSHKAS (see links) where n+1 is the number of desired terms.
CROSSREFS
KEYWORD
nonn
AUTHOR
Doron Zeilberger, Sep 18 2009
EXTENSIONS
Edited by Charles R Greathouse IV, Oct 28 2009
STATUS
approved