login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Triangle read by rows where T(n,k) is the number of strict integer partitions of n with k distinct sums of nonempty subsets.
8

%I #5 Sep 30 2023 09:22:18

%S 1,0,1,0,1,0,0,1,0,1,0,1,0,1,0,0,1,0,2,0,0,0,1,0,2,0,0,1,0,1,0,3,0,0,

%T 0,1,0,1,0,3,0,0,1,1,0,0,1,0,4,0,0,0,3,0,0,0,1,0,4,0,0,2,2,0,0,1,0,1,

%U 0,5,0,0,0,5,0,0,0,1,0,1,0,5,0,0,2,5,0,0,0,0,2

%N Triangle read by rows where T(n,k) is the number of strict integer partitions of n with k distinct sums of nonempty subsets.

%e The partition (7,6,1) has sums 1, 6, 7, 8, 13, 14, so is counted under T(14,6).

%e Triangle begins:

%e 1

%e 0 1

%e 0 1 0

%e 0 1 0 1

%e 0 1 0 1 0

%e 0 1 0 2 0 0

%e 0 1 0 2 0 0 1

%e 0 1 0 3 0 0 0 1

%e 0 1 0 3 0 0 1 1 0

%e 0 1 0 4 0 0 0 3 0 0

%e 0 1 0 4 0 0 2 2 0 0 1

%e 0 1 0 5 0 0 0 5 0 0 0 1

%e 0 1 0 5 0 0 2 5 0 0 0 0 2

%e 0 1 0 6 0 0 0 8 0 0 0 1 0 2

%e 0 1 0 6 0 0 3 7 0 0 0 0 3 1 1

%e 0 1 0 7 0 0 0 12 0 0 0 1 0 4 0 2

%e 0 1 0 7 0 0 3 11 0 0 0 1 3 2 2 1 1

%e 0 1 0 8 0 0 0 16 0 0 0 1 0 7 0 3 0 2

%e 0 1 0 8 0 0 4 15 0 0 0 1 3 3 6 2 0 0 3

%e 0 1 0 9 0 0 0 21 0 0 0 2 0 9 0 7 0 1 0 4

%e 0 1 0 9 0 0 4 20 0 0 1 0 4 8 5 5 0 0 2 0 5

%e Row n = 14 counts the following partitions (A..E = 10..14):

%e (E) . (D1) . . (761) (B21) . . . . (6521) (8321) (7421)

%e (C2) (752) (A31) (6431)

%e (B3) (743) (941) (5432)

%e (A4) (932)

%e (95) (851)

%e (86) (842)

%e (653)

%t Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&Length[Union[Total/@Rest[Subsets[#]]]]==k&]],{n,0,15},{k,0,n}]

%Y Row sums are A000009.

%Y Rightmost column n = k is A188431, non-strict A126796.

%Y The one-based weighted row sums are A284640.

%Y The corresponding rank statistic is A299701.

%Y The non-strict version is A365658.

%Y Central column n = 2k in the non-strict case is A365660.

%Y Reverse-weighted row-sums are A365922, non-strict A276024.

%Y A000041 counts integer partitions.

%Y A000124 counts distinct sums of subsets of {1..n}.

%Y A365543 counts partitions with a submultiset summing to k, strict A365661.

%Y Cf. A046663, A108917, A122768, A137719, A304792, A364916.

%K nonn,tabl

%O 0,19

%A _Gus Wiseman_, Sep 28 2023