A347730 Number of compositions (ordered partitions) of n into at most 2 triangular numbers.

1, 1, 1, 1, 2, 0, 2, 2, 0, 2, 1, 2, 1, 2, 0, 1, 4, 0, 2, 0, 1, 3, 2, 0, 2, 2, 0, 2, 1, 2, 1, 4, 0, 0, 2, 0, 3, 2, 2, 2, 0, 0, 3, 2, 0, 1, 4, 0, 2, 2, 0, 4, 0, 0, 0, 3, 3, 2, 2, 0, 2, 2, 0, 0, 2, 2, 3, 2, 0, 2, 2, 0, 3, 2, 0, 0, 4, 0, 1, 2

Offset

0,5

Links

Table of n, a(n) for n=0..79.

Formula

a(n) = c(n) + Sum_{k=1..n-1} c(k) * c(n-k), where c = A010054. - Wesley Ivan Hurt, Jan 06 2024

Crossrefs

Cf. A000217, A010054, A023361, A053603, A347731, A347732, A347733, A347734.

Sequence in context: A361166 A123530 A161516 * A329491 A123063 A031358

Adjacent sequences: A347727 A347728 A347729 * A347731 A347732 A347733

Keyword

nonn,easy

Author

Ilya Gutkovskiy, Sep 11 2021

Status

approved