A347745 Number of compositions (ordered partitions) of n into at most 3 noncomposite parts.

1, 1, 2, 4, 6, 9, 10, 12, 13, 15, 15, 16, 13, 18, 17, 24, 19, 25, 18, 30, 24, 36, 23, 37, 23, 44, 29, 45, 19, 43, 20, 54, 30, 54, 25, 60, 29, 67, 29, 60, 21, 70, 28, 78, 38, 77, 31, 88, 33, 95, 44, 91, 30, 100, 30, 110, 42, 97, 25, 109, 35, 129, 49, 113, 31, 135

Offset

0,3

Comments

"Noncomposite" means "1 or a prime".

Links

Table of n, a(n) for n=0..65.

Mathematica

Table[Length@Flatten[Permutations/@IntegerPartitions[n, 3, Join[{1}, Prime@Range@PrimePi@n]], 1], {n, 0, 65}] (* Giorgos Kalogeropoulos, Sep 12 2021 *)

Crossrefs

Cf. A008578, A280917, A283762, A347740, A347744.

Sequence in context: A162202 A210380 A228359 * A156165 A024968 A047411

Adjacent sequences: A347742 A347743 A347744 * A347746 A347747 A347748

Keyword

nonn

Author

Ilya Gutkovskiy, Sep 11 2021

Status

approved