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Heinz numbers of integer partitions that are the vertex-degrees of some set multipartition (multiset of nonempty sets) with no singletons.
(history; published version)
#9 by Susanna Cuyler at Mon May 24 00:13:29 EDT 2021
STATUS

proposed

approved

#8 by Gus Wiseman at Sun May 23 10:01:31 EDT 2021
STATUS

editing

proposed

#7 by Gus Wiseman at Sun May 23 10:00:32 EDT 2021
CROSSREFS

The conjugate case of equality is A340387, counted by A035363.

The conjugate version is A344291, also counted by A110618.

The opposite conjugate version is A344296, counted by A025065.

The opposite version is A344414, also counted by A025065.

The case of equality is A344415, also counted by A035363.

The opposite even-weight version is A344416, counted by A000070.

A000070 counts non-multigraphical partitions.

A025065 counts palindromic partitions.

A035363 counts partitions into even parts.

#6 by Gus Wiseman at Sun May 23 09:54:41 EDT 2021
COMMENTS

Also Heinz numbers of partitions whose greatest part is less than or equal to half their the sum of parts, i.e., numbers n whose sum of prime indices A056239(n) is at least twice their the greatest prime index A061395(n). - Gus Wiseman, May 23 2021

#5 by Gus Wiseman at Sun May 23 05:49:38 EDT 2021
COMMENTS

Also Heinz numbers of partitions whose greatest part is less than or equal to half their sum of parts, i.e., numbers n whose sum of prime indices A056239(n) is at least twice their greatest prime index A061395(n). - Gus Wiseman, May 23 2021

FORMULA

A061395(a(n)) <= A056239(a(n))/2.

CROSSREFS

These partitions are counted by A110618.

The even-weight version is A320924.

The conjugate case of equality is A340387, counted by A035363.

The conjugate version is A344291, also counted by A110618.

The opposite conjugate version is A344296, counted by A025065.

The opposite version is A344414, also counted by A025065.

The case of equality is A344415, also counted by A035363.

The opposite even-weight version is A344416, counted by A000070.

A056239 adds up prime indices, row sums of A112798.

A058696 counts partitions of even numbers, ranked by A300061.

A334201 adds up all prime indices except the greatest.

Cf. A000070, A000041, A000569, A056239, A110618, A112798, A265640, A283877, A306005, A318361, A320922, A320923, A320924, A320925.

STATUS

approved

editing

#4 by Susanna Cuyler at Tue Nov 27 16:17:47 EST 2018
STATUS

proposed

approved

#3 by Gus Wiseman at Mon Nov 26 23:09:02 EST 2018
STATUS

editing

proposed

#2 by Gus Wiseman at Mon Nov 26 20:42:11 EST 2018
NAME

allocated for Gus WisemanHeinz numbers of integer partitions that are the vertex-degrees of some set multipartition (multiset of nonempty sets) with no singletons.

DATA

1, 4, 8, 9, 12, 16, 18, 24, 25, 27, 30, 32, 36, 40, 45, 48, 49, 50, 54, 60, 63, 64, 70, 72, 75, 80, 81, 84, 90, 96, 98, 100, 105, 108, 112, 120, 121, 125, 126, 128, 135, 140, 144, 147, 150, 154, 160, 162, 165, 168, 169, 175, 180, 189, 192, 196, 198, 200, 210

OFFSET

1,2

COMMENTS

The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).

EXAMPLE

Each term paired with its Heinz partition and a realizing set multipartition with no singletons:

1: (): {}

4: (11): {{1,2}}

8: (111): {{1,2,3}}

9: (22): {{1,2},{1,2}}

12: (211): {{1,2},{1,3}}

16: (1111): {{1,2,3,4}}

18: (221): {{1,2},{1,2,3}}

24: (2111): {{1,2},{1,3,4}}

25: (33): {{1,2},{1,2},{1,2}}

27: (222): {{1,2,3},{1,2,3}}

30: (321): {{1,2},{1,2},{1,3}}

32: (11111): {{1,2,3,4,5}}

36: (2211): {{1,2},{1,2,3,4}}

40: (3111): {{1,2},{1,3},{1,4}}

MATHEMATICA

nrmptn[n_]:=Join@@MapIndexed[Table[#2[[1]], {#1}]&, If[n==1, {}, Flatten[Cases[FactorInteger[n]//Reverse, {p_, k_}:>Table[PrimePi[p], {k}]]]]];

sqnopfacs[n_]:=If[n<=1, {{}}, Join@@Table[Map[Prepend[#, d]&, Select[sqnopfacs[n/d], Min@@#>=d&]], {d, Select[Rest[Divisors[n]], !PrimeQ[#]&&SquareFreeQ[#]&]}]]

Select[Range[100], Length[sqnopfacs[Times@@Prime/@nrmptn[#]]]>0&]

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Nov 26 2018

STATUS

approved

editing

#1 by Gus Wiseman at Mon Nov 26 20:42:11 EST 2018
NAME

allocated for Gus Wiseman

KEYWORD

allocated

STATUS

approved