A330665 - OEIS

A330665

Number of balanced reduced multisystems of maximal depth whose atoms are the prime indices of n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 5, 1, 1, 1, 2, 1, 3, 1, 5, 1, 1, 1, 7, 1, 1, 1, 5, 1, 3, 1, 2, 2, 1, 1, 16, 1, 2, 1, 2, 1, 5, 1, 5, 1, 1, 1, 11, 1, 1, 2, 16, 1, 3, 1, 2, 1, 3, 1, 27, 1, 1, 2, 2, 1, 3, 1, 16, 2, 1, 1, 11, 1

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OFFSET

1,12

COMMENTS

First differs from A317145 at a(32) = 5, A317145(32) = 4.

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.

Also series/singleton-reduced factorizations of n with Omega(n) levels of parentheses. See A001055, A050336, A050338, A050340, etc.

LINKS

Table of n, a(n) for n=1..85.

FORMULA

a(2^n) = A000111(n - 1).

a(product of n distinct primes) = A006472(n).

EXAMPLE

The a(n) multisystems for n = 2, 6, 12, 24, 48:

{1} {1,2} {{1},{1,2}} {{{1}},{{1},{1,2}}} {{{{1}}},{{{1}},{{1},{1,2}}}}

{{2},{1,1}} {{{1,1}},{{1},{2}}} {{{{1}}},{{{1,1}},{{1},{2}}}}

{{{1}},{{2},{1,1}}} {{{{1},{1}}},{{{1}},{{1,2}}}}

{{{1,2}},{{1},{1}}} {{{{1},{1,1}}},{{{1}},{{2}}}}

{{{2}},{{1},{1,1}}} {{{{1,1}}},{{{1}},{{1},{2}}}}

{{{{1}}},{{{1}},{{2},{1,1}}}}

{{{{1}}},{{{1,2}},{{1},{1}}}}

{{{{1},{1}}},{{{2}},{{1,1}}}}

{{{{1},{1,2}}},{{{1}},{{1}}}}

{{{{1,1}}},{{{2}},{{1},{1}}}}

{{{{1}}},{{{2}},{{1},{1,1}}}}

{{{{1},{2}}},{{{1}},{{1,1}}}}

{{{{1,2}}},{{{1}},{{1},{1}}}}

{{{{2}}},{{{1}},{{1},{1,1}}}}

{{{{2}}},{{{1,1}},{{1},{1}}}}

{{{{2},{1,1}}},{{{1}},{{1}}}}

MATHEMATICA

primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];

sps[{}]:={{}}; sps[set:{i_, ___}]:=Join@@Function[s, Prepend[#, s]&/@sps[Complement[set, s]]]/@Cases[Subsets[set], {i, ___}];

mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]];

totm[m_]:=Prepend[Join@@Table[totm[p], {p, Select[mps[m], 1<Length[#]<Length[m]&]}], m];

Table[Length[Select[totm[primeMS[n]], Length[#]<=1||Depth[#]==PrimeOmega[n]&]], {n, 100}]

CROSSREFS

The last nonzero term in row n of A330667 is a(n).

The chain version is A317145.

The non-maximal version is A318812.

Unlabeled versions are A330664 and A330663.

Other labeled versions are A330675 (strongly normal) and A330676 (normal).

Cf. A001055, A005121, A005804, A050336, A213427, A292505, A317144, A318849, A320160, A330474, A330475, A330679.

Sequence in context: A375120 A300385 A317145 * A345985 A103765 A344772

Adjacent sequences: A330662 A330663 A330664 * A330666 A330667 A330668

KEYWORD

nonn

AUTHOR

Gus Wiseman, Dec 27 2019

STATUS

approved