login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A351268
Sum of the 5th powers of the squarefree divisors of n.
11
1, 33, 244, 33, 3126, 8052, 16808, 33, 244, 103158, 161052, 8052, 371294, 554664, 762744, 33, 1419858, 8052, 2476100, 103158, 4101152, 5314716, 6436344, 8052, 3126, 12252702, 244, 554664, 20511150, 25170552, 28629152, 33, 39296688, 46855314, 52541808, 8052, 69343958
OFFSET
1,2
COMMENTS
Inverse Möbius transform of n^5 * mu(n)^2. - Wesley Ivan Hurt, Jun 08 2023
LINKS
N. J. A. Sloane, Transforms.
FORMULA
a(n) = Sum_{d|n} d^5 * mu(d)^2.
Multiplicative with a(p^e) = 1 + p^5. - Amiram Eldar, Feb 06 2022
G.f.: Sum_{k>=1} mu(k)^2 * k^5 * x^k / (1 - x^k). - Ilya Gutkovskiy, Feb 06 2022
Sum_{k=1..n} a(k) ~ c * n^6, where c = zeta(6)/(6*zeta(2)) = Pi^4/945 = 0.103078... . - Amiram Eldar, Nov 10 2022
EXAMPLE
a(4) = 33; a(4) = Sum_{d|4} d^5 * mu(d)^2 = 1^5*1 + 2^5*1 + 4^4*0 = 33.
MATHEMATICA
a[1] = 1; a[n_] := Times @@ (1 + FactorInteger[n][[;; , 1]]^5); Array[a, 100] (* Amiram Eldar, Feb 06 2022 *)
CROSSREFS
Cf. A008683 (mu), A013661, A013664.
Sum of the k-th powers of the squarefree divisors of n for k=0..10: A034444 (k=0), A048250 (k=1), A351265 (k=2), A351266 (k=3), A351267 (k=4), this sequence (k=5), A351269 (k=6), A351270 (k=7), A351271 (k=8), A351272 (k=9), A351273 (k=10).
Sequence in context: A274639 A306879 A178448 * A088703 A321561 A034679
KEYWORD
nonn,mult
AUTHOR
Wesley Ivan Hurt, Feb 05 2022
STATUS
approved