A326592 Sum of the seventh largest parts in the partitions of n into 10 parts.
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 5, 7, 11, 16, 24, 34, 49, 66, 92, 123, 167, 220, 293, 380, 497, 636, 818, 1035, 1312, 1642, 2059, 2551, 3162, 3884, 4769, 5806, 7068, 8539, 10310, 12370, 14826, 17670, 21038, 24920, 29482, 34725, 40848, 47852, 55989
Offset: 0
Keywords
Crossrefs
Programs
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Mathematica
Table[Sum[Sum[Sum[Sum[Sum[Sum[Sum[Sum[Sum[o, {i, j, Floor[(n - j - k - l - m - o - p - q - r)/2]}], {j, k, Floor[(n - k - l - m - o - p - q - r)/3]}], {k, l, Floor[(n - l - m - o - p - q - r)/4]}], {l, m, Floor[(n - m - o - p - q - r)/5]}], {m, o, Floor[(n - o - p - q - r)/6]}], {o, p, Floor[(n - p - q - r)/7]}], {p, q, Floor[(n - q - r)/8]}], {q, r, Floor[(n - r)/9]}], {r, Floor[n/10]}], {n, 0, 50}] Table[Total[IntegerPartitions[n,{10}][[;;,7]]],{n,0,60}] (* Harvey P. Dale, Jul 14 2025 *)
Formula
a(n) = Sum_{r=1..floor(n/10)} Sum_{q=r..floor((n-r)/9)} Sum_{p=q..floor((n-q-r)/8)} Sum_{o=p..floor((n-p-q-r)/7)} Sum_{m=o..floor((n-o-p-q-r)/6)} Sum_{l=m..floor((n-m-o-p-q-r)/5)} Sum_{k=l..floor((n-l-m-o-p-q-r)/4)} Sum_{j=k..floor((n-k-l-m-o-p-q-r)/3)} Sum_{i=j..floor((n-j-k-l-m-o-p-q-r)/2)} o.