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”).

A347730
Number of compositions (ordered partitions) of n into at most 2 triangular numbers.
5
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
FORMULA
a(n) = c(n) + Sum_{k=1..n-1} c(k) * c(n-k), where c = A010054. - Wesley Ivan Hurt, Jan 06 2024
KEYWORD
nonn,easy
AUTHOR
Ilya Gutkovskiy, Sep 11 2021
STATUS
approved