A309624 - OEIS

%I #5 Aug 10 2019 19:14:50

%S 0,0,0,0,0,0,0,7,6,14,18,37,46,83,106,179,230,352,450,667,838,1169,

%T 1458,1978,2442,3214,3934,5074,6154,7768,9332,11631,13854,16975,20086,

%U 24341,28572,34244,39942,47430,54998,64708,74598,87157,99936,115874,132234

%N Sum of the odd parts in the partitions of n into 7 parts.

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

%F a(n) = Sum_{o=1..floor(n/7)} Sum_{m=o..floor((n-o)/6)} Sum_{l=m..floor((n-m-o)/5)} Sum_{k=l..floor((n-l-m-o)/4)} Sum_{j=k..floor((n-k-l-m-o)/3} Sum_{i=j..floor((n-j-k-l-m-o)/2)} o * (o mod 2) + m * (m mod 2) + l * (l mod 2) + k * (k mod 2) + j * (j mod 2) + i * (i mod 2) + (n-i-j-k-l-m-o) * ((n-i-j-k-l-m-o) mod 2).

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

%K nonn

%O 0,8

%A _Wesley Ivan Hurt_, Aug 10 2019