OFFSET
0,12
FORMULA
a(n) = Sum_{q=1..floor(n/9)} Sum_{p=q..floor((n-q)/8)} Sum_{o=p..floor((n-p-q)/7)} Sum_{m=o..floor((n-o-p-q)/6)} Sum_{l=m..floor((n-m-o-p-q)/5)} Sum_{k=l..floor((n-l-m-o-p-q)/4)} Sum_{j=k..floor((n-k-l-m-o-p-q)/3)} Sum_{i=j..floor((n-j-k-l-m-o-p-q)/2)} i.
MATHEMATICA
Table[Total[IntegerPartitions[n, {9}][[;; , 2]]], {n, 0, 50}] (* _Harvey P. Dale_, Dec 03 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
_Wesley Ivan Hurt_, Jul 10 2019
STATUS
approved