A308960 - OEIS

%I #6 Jul 03 2019 06:13:11

%S 0,0,0,0,0,0,0,1,2,5,5,13,19,34,40,58,77,118,139,194,232,324,385,508,

%T 576,775,883,1133,1274,1630,1821,2262,2525,3093,3450,4153,4563,5494,

%U 6067,7155,7842,9283,10177,11860,12928,15051,16466,18969,20543,23705,25820

%N Sum of the largest parts in the partitions of n into 7 squarefree 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)} 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)^2 * (n-i-j-k-l-m-o), where mu is the Möbius function (A008683).

%F a(n) = A308953(n) - A308954(n) - A308955(n) - A308956(n) - A308957(n) - A308958(n) - A308959(n).

%t Table[Sum[Sum[Sum[Sum[Sum[Sum[(n-i-j-k-l-m-o) * MoebiusMu[o]^2 * MoebiusMu[m]^2 * MoebiusMu[l]^2 * MoebiusMu[k]^2 * MoebiusMu[j]^2 * MoebiusMu[i]^2 * MoebiusMu[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}]

%Y Cf. A008683, A308952, A308953, A308954, A308955, A308956, A308957, A308958, A308959.

%K nonn

%O 0,9

%A _Wesley Ivan Hurt_, Jul 03 2019