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”).

A309438
Number of prime parts in the partitions of n into 9 parts.
1
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 3, 5, 11, 17, 30, 45, 72, 104, 147, 200, 279, 367, 491, 633, 825, 1042, 1330, 1649, 2063, 2531, 3116, 3776, 4597, 5510, 6627, 7878, 9381, 11058, 13059, 15275, 17895, 20802, 24191, 27942, 32303, 37099, 42628, 48719, 55678
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)} (c(q) + c(p) + c(o) + c(m) + c(l) + c(k) + c(j) + c(i) + c(n-i-j-k-l-m-o-p-q)), where c = A010051.
MATHEMATICA
Table[Count[Flatten[IntegerPartitions[n, {9}]], _?PrimeQ], {n, 0, 50}] (* Harvey P. Dale, Jun 12 2021 *)
CROSSREFS
Sequence in context: A309433 A309436 A309437 * A309439 A108542 A006450
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Aug 03 2019
STATUS
approved