A325835 Number of integer partitions of 2*n having one more distinct submultiset than distinct subset-sums.

0, 0, 1, 2, 3, 5, 9, 10, 14, 22, 30, 33, 46, 52, 74, 107, 101, 123, 171, 182, 225

Offset

0,4

Comments

The number of submultisets of a partition is the product of its multiplicities, each plus one. A subset-sum of an integer partition is the sum of some submultiset of its parts. These are partitions with one subset-sum which is the sum of two distinct submultisets, while all others are the sum of only one submultiset.

The Heinz numbers of these partitions are given by A325802.

Links

Table of n, a(n) for n=0..20.

Example

The a(2) = 1 through a(8) = 14 partitions:
  (211)  (321)   (422)    (532)     (633)      (743)       (844)
         (3111)  (431)    (541)     (642)      (752)       (853)
                 (41111)  (5221)    (651)      (761)       (862)
                          (5311)    (4332)     (7322)      (871)
                          (511111)  (5331)     (7331)      (5443)
                                    (6222)     (7421)      (7441)
                                    (6411)     (7511)      (7531)
                                    (33222)    (72221)     (8332)
                                    (6111111)  (74111)     (8521)
                                               (71111111)  (8611)
                                                           (82222)
                                                           (83311)
                                                           (85111)
                                                           (811111111)
For example, the partition (7,5,3,1) has submultisets (), (1), (3), (5), (7), (3,1), (5,1), (5,3), (7,1), (7,3), (7,5), (5,3,1), (7,3,1), (7,5,1), (7,5,3), (7,5,3,1), all of which have different sums except for (5,3) and (7,1), which both sum to 8, so (7,5,3,1) is counted under a(8).

Mathematica

Table[Length[Select[IntegerPartitions[n], Times@@(1+Length/@Split[#])==1+Length[Union[Total/@Subsets[#]]]&]], {n, 0, 20, 2}]

Crossrefs

Cf. A002033, A088880, A088881, A108917, A126796, A276024, A325799, A325800, A325801, A325802, A325828, A325830, A325833, A325836.

Sequence in context: A226820 A072192 A287158 * A050158 A057254 A057242

Adjacent sequences: A325832 A325833 A325834 * A325836 A325837 A325838

Keyword

nonn,more

Author

Gus Wiseman, May 29 2019

Status

approved