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A344043 a(n) = n * Sum_{d|n} sigma(d)^3 / d. 3
1, 29, 67, 401, 221, 1943, 519, 4177, 2398, 6409, 1739, 26867, 2757, 15051, 14807, 38145, 5849, 69542, 8019, 88621, 34773, 50431, 13847, 279859, 30896, 79953, 71194, 208119, 27029, 429403, 32799, 326337, 116513, 169621, 114699, 961598, 54909, 232551, 184719, 923117, 74129, 1008417, 85227, 697339 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..44.

FORMULA

G.f.: Sum_{k >= 1} sigma(k)^3 * x^k/(1 - x^k)^2.

MATHEMATICA

a[n_] := n * DivisorSum[n, DivisorSigma[1, #]^3/# &]; Array[a, 44] (* Amiram Eldar, May 08 2021 *)

PROG

(PARI) a(n) = n*sumdiv(n, d, sigma(d)^3/d);

(PARI) my(N=66, x='x+O('x^N)); Vec(sum(k=1, N, sigma(k)^3*x^k/(1-x^k)^2))

CROSSREFS

Cf. A060640, A226565, A226566, A344044.

Sequence in context: A294615 A182332 A163426 * A165945 A226892 A183194

Adjacent sequences:  A344040 A344041 A344042 * A344044 A344045 A344046

KEYWORD

nonn,mult

AUTHOR

Seiichi Manyama, May 08 2021

STATUS

approved

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Last modified July 25 09:49 EDT 2021. Contains 346289 sequences. (Running on oeis4.)