A326459 - OEIS

%I #7 Nov 18 2021 14:53:54

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,4,4,7,9,10,12,15,17,20,24,24,

%T 30,39,43,47,60,58,75,81,94,97,124,116,152,146,180,172,229,207,278,

%U 246,320,298,400,332,464,395,539,463,643,521,749,612,855,720

%N Sum of the fifth largest parts of the partitions of n into 8 primes.

%H <a href="/index/Par#part">Index entries for sequences related to partitions</a>

%F a(n) = Sum_{p=1..floor(n/8)} Sum_{o=p..floor((n-p)/7)} Sum_{m=o..floor((n-o-p)/6)} Sum_{l=m..floor((n-m-o-p)/5)} Sum_{k=l..floor((n-l-m-o-p)/4)} Sum_{j=k..floor((n-k-l-m-o-p)/3)} Sum_{i=j..floor((n-j-k-l-m-o-p)/2)} c(p) * c(o) * c(m) * c(l) * c(k) * c(j) * c(i) * c(n-i-j-k-l-m-o-p) * l, where c = A010051.

%F a(n) = A326455(n) - A326456(n) - A326457(n) - A326458(n) - A326460(n) - A326461(n) - A326462(n) - A326463(n).

%t Table[Sum[Sum[Sum[Sum[Sum[Sum[Sum[l * (PrimePi[i] - PrimePi[i - 1]) (PrimePi[j] - PrimePi[j - 1]) (PrimePi[k] - PrimePi[k - 1]) (PrimePi[l] - PrimePi[l - 1]) (PrimePi[m] - PrimePi[m - 1]) (PrimePi[o] - PrimePi[o - 1]) (PrimePi[p] - PrimePi[p - 1]) (PrimePi[n - i - j - k - l - m - o - p] - PrimePi[n - i - j - k - l - m - o - p - 1]), {i, j, Floor[(n - j - k - l - m - o - p)/2]}], {j, k, Floor[(n - k - l - m - o - p)/3]}], {k, l, Floor[(n - l - m - o - p)/4]}], {l, m, Floor[(n - m - o - p)/5]}], {m, o, Floor[(n - o - p)/6]}], {o, p, Floor[(n - p)/7]}], {p, Floor[n/8]}], {n, 0, 50}]

%Y Cf. A010051, A259198, A326455, A326456, A326457, A326458, A326460, A326461, A326462, A326463.

%K nonn

%O 0,17

%A _Wesley Ivan Hurt_, Jul 06 2019