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A330666 Number of non-isomorphic balanced reduced multisystems whose degrees (atom multiplicities) are the weakly decreasing prime indices of n. 5
1, 1, 1, 1, 2, 3, 6, 2, 10, 11, 20, 15, 90, 51, 80, 6, 468, 93, 2910, 80, 521, 277, 20644, 80, 334, 1761, 393, 521, 165874, 1374 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

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.

A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. A multiset whose multiplicities are the prime indices of n (such as row n of A305936) is generally not the same as the multiset of prime indices of n. For example, the prime indices of 12 are {1,1,2}, while a multiset whose multiplicities are {1,1,2} is {1,1,2,3}.

LINKS

Table of n, a(n) for n=1..30.

FORMULA

a(2^n) = a(prime(n)) = A318813(n).

EXAMPLE

Non-isomorphic representatives of the a(2) = 1 through a(9) = 10 multisystems (commas and outer brackets elided):

    1  11  12  111      112      1111            123      1122

               {1}{11}  {1}{12}  {1}{111}        {1}{23}  {1}{122}

                        {2}{11}  {11}{11}                 {11}{22}

                                 {1}{1}{11}               {12}{12}

                                 {{1}}{{1}{11}}           {1}{1}{22}

                                 {{11}}{{1}{1}}           {1}{2}{12}

                                                          {{1}}{{1}{22}}

                                                          {{11}}{{2}{2}}

                                                          {{1}}{{2}{12}}

                                                          {{12}}{{1}{2}}

Non-isomorphic representatives of the a(12) = 15 multisystems:

  {1,1,2,3}

  {{1},{1,2,3}}

  {{1,1},{2,3}}

  {{1,2},{1,3}}

  {{2},{1,1,3}}

  {{1},{1},{2,3}}

  {{1},{2},{1,3}}

  {{2},{3},{1,1}}

  {{{1}},{{1},{2,3}}}

  {{{1,1}},{{2},{3}}}

  {{{1}},{{2},{1,3}}}

  {{{1,2}},{{1},{3}}}

  {{{2}},{{1},{1,3}}}

  {{{2}},{{3},{1,1}}}

  {{{2,3}},{{1},{1}}}

CROSSREFS

The labeled version is A318846.

The maximum-depth version is A330664.

Unlabeled balanced reduced multisystems by weight are A330474.

The case of constant or strict atoms is A318813.

Cf. A000669, A005121, A007716, A048816, A141268, A306186, A317791, A318812, A318849, A330470, A330475, A330655, A330728.

Sequence in context: A073546 A216975 A275666 * A319432 A115033 A214630

Adjacent sequences:  A330663 A330664 A330665 * A330667 A330668 A330669

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Dec 30 2019

STATUS

approved

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Last modified July 27 15:06 EDT 2021. Contains 346307 sequences. (Running on oeis4.)