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A283533 a(n) = Sum_{d|n} d^(2*d + 1). 8
1, 33, 2188, 262177, 48828126, 13060696236, 4747561509944, 2251799813947425, 1350851717672994277, 1000000000000048828158, 895430243255237372246532, 953962166440690142662256812, 1192533292512492016559195008118 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Inverse Mobius transform of A085526. - R. J. Mathar, Mar 11 2017
LINKS
FORMULA
L.g.f.: -log(Product_{k>=1} (1 - x^k)^(k^(2*k))) = Sum_{k>=1} a(k)*x^k/k. - Seiichi Manyama, Jun 18 2019
EXAMPLE
a(6) = 1^(2+1) + 2^(4+1) + 3^(6+1) + 6^(12+1) = 13060696236.
MATHEMATICA
f[n_] := Block[{d = Divisors[n]}, Total[d^(2 d + 1)]]; Array[f, 14] (* Robert G. Wilson v, Mar 10 2017 *)
PROG
(PARI) a(n) = sumdiv(n, d, d^(2*d+1)); \\ Michel Marcus, Mar 11 2017
(PARI) N=20; x='x+O('x^N); Vec(x*deriv(-log(prod(k=1, N, (1-x^k)^k^(2*k))))) \\ Seiichi Manyama, Jun 18 2019
CROSSREFS
Cf. Sum_{d|n} d^(k*d+1): A283498 (k=1), this sequence (k=2), A283535 (k=3).
Cf. A308696.
Sequence in context: A284112 A099370 A267672 * A294773 A294611 A294954
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 10 2017
STATUS
approved

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Last modified June 22 15:57 EDT 2024. Contains 373590 sequences. (Running on oeis4.)