A292432 Number of normal multisets that cannot be expressed as the multiset-union of a set of sets.

0, 1, 1, 3, 5, 9, 16, 27, 46, 76

Offset

1,4

Comments

A multiset is normal if it spans an initial interval of positive integers. Most normal multisets can be expressed as the multiset-union of a set of sets. For example, {1,1,2,2} is the multiset-union of {{1},{2},{1,2}}.

Links

Table of n, a(n) for n=1..10.

Example

The a(6) = 9 multisets are: {1,1,1,1,1,1}, {1,1,1,1,1,2}, {1,1,1,1,2,2}, {1,1,1,1,2,3}, {1,1,1,2,2,2}, {1,1,2,2,2,2}, {1,2,2,2,2,2}, {1,2,2,2,2,3}, {1,2,3,3,3,3}.

Crossrefs

Cf. A049311, A089259, A116540, A283877, A292444.

Sequence in context: A337596 A355115 A023656 * A129973 A018159 A094980

Adjacent sequences: A292429 A292430 A292431 * A292433 A292434 A292435

Keyword

nonn,more

Author

Gus Wiseman, Oct 02 2017

Status

approved