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A336128
Number of ways to split a strict composition of n into contiguous subsequences with different sums.
19
1, 1, 1, 5, 5, 9, 29, 37, 57, 89, 265, 309, 521, 745, 1129, 3005, 3545, 5685, 8201, 12265, 16629, 41369, 48109, 77265, 107645, 160681, 214861, 316913, 644837, 798861, 1207445, 1694269, 2437689, 3326705, 4710397, 6270513, 12246521, 14853625, 22244569, 30308033, 43706705, 57926577, 82166105, 107873221, 148081785, 257989961, 320873065, 458994657, 628016225, 875485585, 1165065733
OFFSET
0,4
COMMENTS
A composition of n is a finite sequence of positive integers summing to n.
EXAMPLE
The a(0) = 1 through a(5) = 5 splits:
() (1) (2) (3) (4) (5)
(12) (13) (14)
(21) (31) (23)
(1)(2) (1)(3) (32)
(2)(1) (3)(1) (41)
(1)(4)
(2)(3)
(3)(2)
(4)(1)
The a(6) = 29 splits:
(6) (1)(5) (1)(2)(3)
(15) (2)(4) (1)(3)(2)
(24) (4)(2) (2)(1)(3)
(42) (5)(1) (2)(3)(1)
(51) (1)(23) (3)(1)(2)
(123) (1)(32) (3)(2)(1)
(132) (13)(2)
(213) (2)(13)
(231) (2)(31)
(312) (23)(1)
(321) (31)(2)
(32)(1)
MATHEMATICA
splits[dom_]:=Append[Join@@Table[Prepend[#, Take[dom, i]]&/@splits[Drop[dom, i]], {i, Length[dom]-1}], {dom}];
Table[Sum[Length[Select[splits[ctn], UnsameQ@@Total/@#&]], {ctn, Join@@Permutations/@Select[IntegerPartitions[n], UnsameQ@@#&]}], {n, 0, 15}]
CROSSREFS
The version with equal instead of different sums is A336130.
Starting with a non-strict composition gives A336127.
Starting with a partition gives A336131.
Starting with a strict partition gives A336132.
Partitions of partitions are A001970.
Partitions of compositions are A075900.
Compositions of compositions are A133494.
Set partitions with distinct block-sums are A275780.
Compositions of partitions are A323583.
Sequence in context: A173322 A097910 A321655 * A049122 A336140 A321660
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 10 2020
EXTENSIONS
a(31)-a(50) from Max Alekseyev, Feb 14 2024
STATUS
approved