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A326630
Sum of the eighth largest parts in the partitions of n into 10 squarefree parts.
11
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 4, 5, 8, 9, 14, 18, 26, 30, 41, 50, 66, 77, 100, 117, 152, 174, 219, 252, 314, 357, 436, 499, 605, 685, 820, 929, 1109, 1243, 1469, 1650, 1947, 2169, 2536, 2833, 3297, 3663, 4235, 4707, 5424, 6000, 6867, 7604, 8684
OFFSET
0,13
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)} mu(r)^2 * mu(q)^2 * mu(p)^2 * mu(o)^2 * mu(m)^2 * mu(l)^2 * mu(k)^2 * mu(j)^2 * mu(i)^2 * mu(n-i-j-k-l-m-o-p-q-r)^2 * p, where mu is the Möbius function (A008683).
a(n) = A326627(n) - A326628(n) - A326629(n) - A326631(n) - A326632(n) - A326633(n) - A326634(n) - A326635(n) - A326636(n) - A326637(n).
MATHEMATICA
Table[Select[IntegerPartitions[n, {10}], AllTrue[#, SquareFreeQ]&][[All, 8]]//Total, {n, 0, 60}] (* Harvey P. Dale, Apr 19 2020 *)
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Jul 14 2019
STATUS
approved