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A357451
Number of compositions (ordered partitions) of n into tribonacci numbers 1,2,4,7,13,24, ... (A000073).
2
1, 1, 2, 3, 6, 10, 18, 32, 57, 101, 179, 318, 564, 1002, 1778, 3157, 5603, 9947, 17656, 31342, 55635, 98759, 175308, 311191, 552400, 980571, 1740625, 3089803, 5484750, 9736045, 17282576, 30678512, 54457808, 96668726, 171597851, 304605465, 540708924
OFFSET
0,3
FORMULA
G.f.: 1 / (1 - Sum_{k>=3} x^A000073(k)).
MATHEMATICA
A000073[0] = A000073[1] = 0; A000073[2] = 1; A000073[n_] := A000073[n] = A000073[n - 1] + A000073[n - 2] + A000073[n - 3]; nmax = 36; CoefficientList[Series[1/(1 - Sum[x^A000073[k], {k, 3, 20}]), {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 29 2022
STATUS
approved