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A330464
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Number of non-isomorphic weight-n sets of set-systems with distinct multiset unions.
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0
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OFFSET
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0,3
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COMMENTS
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A set-system is a finite set of finite nonempty sets of positive integers.
As an alternative description, a(n) is the number of non-isomorphic sets of sets of sets with n leaves where the inner sets of sets all have different multiset unions.
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LINKS
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EXAMPLE
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Non-isomorphic representatives of the a(1) = 1 through a(3) = 9 sets:
{} {{{1}}} {{{1,2}}} {{{1,2,3}}}
{{{1},{2}}} {{{1},{1,2}}}
{{{1}},{{2}}} {{{1},{2,3}}}
{{{1}},{{1,2}}}
{{{1}},{{2,3}}}
{{{1},{2},{3}}}
{{{1}},{{1},{2}}}
{{{1}},{{2},{3}}}
{{{1}},{{2}},{{3}}}
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CROSSREFS
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Non-isomorphic sets of sets are A283877.
Non-isomorphic sets of sets of sets are A323790.
Non-isomorphic set partitions of set-systems are A323795.
Cf. A089259, A141268, A271619, A279375, A279785, A306186, A316980, A317533, A318564, A318565, A318566, A330459, A330472.
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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