OFFSET
0,4
COMMENTS
A balanced reduced multisystem is either a finite multiset, or a multiset partition with at least two parts, not all of which are singletons, of a balanced reduced multisystem. The weight of an atom is 1, while the weight of a multiset is the sum of weights of its elements.
EXAMPLE
Non-isomorphic representatives of the a(0) = 1 through a(4) = 11 multisystems:
{} {1} {1,2} {{1},{1,2}} {{{1}},{{1},{1,2}}}
{{1},{2,3}} {{{1}},{{1},{2,3}}}
{{{1,2}},{{1},{1}}}
{{{1}},{{2},{1,2}}}
{{{1,2}},{{1},{2}}}
{{{1}},{{2},{1,3}}}
{{{1,2}},{{1},{3}}}
{{{1}},{{2},{3,4}}}
{{{1,2}},{{3},{4}}}
{{{2}},{{1},{1,3}}}
{{{2,3}},{{1},{1}}}
CROSSREFS
The version with all distinct atoms is A000111.
Non-isomorphic set multipartitions are A049311.
The (non-maximal) tree version is A330626.
Allowing leaves to be multisets gives A330663.
The case with prescribed degrees is A330664.
The version allowing all depths is A330668.
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Dec 30 2019
STATUS
approved