A326524 Sum of the smallest parts of the partitions of n into 9 squarefree parts.
0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 4, 5, 8, 9, 13, 17, 23, 26, 36, 42, 55, 63, 80, 93, 119, 131, 165, 188, 230, 255, 312, 351, 420, 466, 555, 620, 731, 804, 945, 1046, 1216, 1333, 1550, 1702, 1959, 2141, 2452, 2688, 3064, 3334, 3790, 4136, 4673, 5070
Offset: 0
Keywords
Crossrefs
Programs
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Mathematica
Table[Total[Select[IntegerPartitions[n,{9}],AllTrue[#,SquareFreeQ]&][[;;,-1]]],{n,0,60}] (* Harvey P. Dale, Mar 22 2023 *)
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)} 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)^2 * q, where mu is the Möbius function (A008683).