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A351268
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Sum of the 5th powers of the squarefree divisors of n.
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11
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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
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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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
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EXAMPLE
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a(4) = 33; a(4) = Sum_{d|4} d^5 * mu(d)^2 = 1^5*1 + 2^5*1 + 4^4*0 = 33.
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MATHEMATICA
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a[1] = 1; a[n_] := Times @@ (1 + FactorInteger[n][[;; , 1]]^5); Array[a, 100] (* Amiram Eldar, Feb 06 2022 *)
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CROSSREFS
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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).
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KEYWORD
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nonn,mult
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AUTHOR
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STATUS
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approved
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