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Revision History for A237667 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Number of partitions of n such that no part is a sum of two or more other parts.
(history; published version)
#24 by Michael De Vlieger at Fri Aug 11 10:03:31 EDT 2023
STATUS

proposed

approved

#23 by Gus Wiseman at Thu Aug 10 23:58:32 EDT 2023
STATUS

editing

proposed

#22 by Gus Wiseman at Thu Aug 10 18:05:16 EDT 2023
EXAMPLE

The partition y = (5,3,3,1) has no non-singleton submultiset with sum in y, so is counted under a(12).

#21 by Gus Wiseman at Thu Aug 10 08:52:09 EDT 2023
COMMENTS

Counts Includes all knapsack partitions (A108917), but first differs at a(12) = 28, A108917(12) = 25. The difference is accounted for by the non-knapsack partitions: (4332), (5331), (33222).

These are partitions not containing the sum of any non-singleton submultiset of the parts, a variation of non-binary sum-free partitions where parts cannot be re-used, ranked by A364531. The complement is counted by A237668. The binary version is A236912. For re-usable parts we have A364350.

CROSSREFS

The strict case is A364349, binary A364670A364533.

A007865 counts binary sum-free sets w/ re-usable parts, complement A093971.

Cf. A002865, `A025065, ~A026905, ~A007865, A237984, `A275972, A325862, `A326083, A363225, A363226, ~A363260, ~A364347, `A364348, A364350, A364670.

#20 by Gus Wiseman at Wed Aug 09 04:21:15 EDT 2023
COMMENTS

First differs from Counts all knapsack partitions (A108917 ), but first differs at a(12) = 28, A108917(12) = 25. The difference is accounted for by the non-knapsack partitions : (4332), (5331), (33222).

These are partitions not containing the sum of any non-singleton submultiset of the parts, a variation of non-binary sum-free partitions where parts cannot be re-used. The complement is counted by A237668. The binary (2-ary) version is A236912. For re-usable parts we have A364350. [The binary version for re-usable parts is A364345.]

Includes all knapsack partitions (A108917).

#19 by Gus Wiseman at Wed Aug 09 04:07:24 EDT 2023
CROSSREFS

Binary version for subsets w/ re-usable parts: A007865, complement A093971.

The strict case is A364349, binary A364670, with re-usable parts A363226.

A007865 counts binary sum-free sets w/ re-usable parts, complement A093971.

Cf. A002865, `A025065, ~A026905, ~A237984, `A275972, A325862, `A326083, A363225, A363226, ~A363260, ~A364347, `A364348, A364350.

#18 by Gus Wiseman at Wed Aug 09 04:03:34 EDT 2023
CROSSREFS

Cf. A237668, A179009.

The binary Binary version for subsets is A085489, with w/ re-usable parts : A007865 (, complement A093971).

For subsets of {1..n} we have A151897, complement A364534 (binary A088809)A085489.

The binary version is A236912 (, ranks A364461), complement A237113 (ranks A364462).

The binary complement is A237113, ranks A364462.

`The binary complement version with re-usable parts is counted by A363225, ranks A364348A364345, strict A364346.

`The binary version with re-usable parts is A364345, ranks A364347, strict A364346.

`Counting all linear combination of parts gives A364350.

The complement for subsets is A364534, binary A088809.

Cf. A002865, `A025065, ~A026905, ~A237984, `A275972, A325862, `A326083, A363225, ~A363260, ~A364347, `A364348, A364350.

#17 by Gus Wiseman at Wed Aug 09 03:51:11 EDT 2023
COMMENTS

From Gus Wiseman, Aug 09 2023: (Start)

First differs from A108917 at a(12) = 28, A108917(12) = 25. The difference is accounted for by the non-knapsack partitions (4332), (5331), (33222).

These are partitions not containing the sum of any non-singleton submultiset of the parts, a variation of non-binary sum-free partitions where parts cannot be re-used. The complement is counted by A237668. The binary (2-ary) version is A236912. For re-usable parts we have A364350. [The binary version for re-usable parts is A364345.]

Includes all knapsack partitions (A108917).

(End)

EXAMPLE

From Gus Wiseman, Aug 09 2023: (Start)

The partition y = (5,3,1,1) has submultiset (3,1,1) with sum in y, so is not counted under a(10).

The partition y = (5,3,3,1) has no submultiset with sum in y, so is counted under a(12).

The a(1) = 1 through a(8) = 12 partitions:

(1) (2) (3) (4) (5) (6) (7) (8)

(11) (21) (22) (32) (33) (43) (44)

(111) (31) (41) (42) (52) (53)

(1111) (221) (51) (61) (62)

(311) (222) (322) (71)

(11111) (411) (331) (332)

(111111) (421) (521)

(511) (611)

(2221) (2222)

(4111) (3311)

(1111111) (5111)

(11111111)

(End)

MATHEMATICA

Table[Length[Select[IntegerPartitions[n], Intersection[#, Total/@Subsets[#, {2, Length[#]}]]=={}&]], {n, 0, 15}] (* Gus Wiseman, Aug 09 2023 *)

CROSSREFS

The binary version for subsets is A085489, with re-usable parts A007865 (complement A093971).

For subsets of {1..n} we have A151897, complement A364534 (binary A088809).

The binary version is A236912 (ranks A364461), complement A237113 (ranks A364462).

The complement is counted by A237668, ranks A364532.

`The binary complement with re-usable parts is counted by A363225, ranks A364348.

`The binary version with re-usable parts is A364345, ranks A364347, strict A364346.

The strict case is A364349, binary A364670, with re-usable parts A363226.

`Counting all linear combination of parts gives A364350.

These partitions have ranks A364531.

A000041 counts partitions, strict A000009.

A008284 counts partitions by length, strict A008289.

A108917 counts knapsack partitions, ranks A299702.

A323092 counts double-free partitions, ranks A320340.

Cf. A002865, `A025065, ~A026905, ~A237984, `A275972, A325862, `A326083, ~A363260.

STATUS

approved

editing

#16 by Michel Marcus at Sun Feb 23 04:44:08 EST 2014
STATUS

proposed

approved

#15 by Giovanni Resta at Sun Feb 23 04:42:24 EST 2014
STATUS

editing

proposed

Discussion
Sun Feb 23
04:43
Giovanni Resta: I uploaded a program as suggested by Joerg Arndt.