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A308671 a(n) = Sum_{d|n} d^(d^2). 3
1, 17, 19684, 4294967313, 298023223876953126, 10314424798490535546171968756, 256923577521058878088611477224235621321608, 6277101735386680763835789423207666416102355444468329480209 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
L.g.f.: -log(Product_{k>=1} (1 - x^k)^(k^(k^2-1))) = Sum_{k>=1} a(k)*x^k/k.
MATHEMATICA
a[n_] := DivisorSum[n, #^(#^2) &]; Array[a, 8] (* Amiram Eldar, May 11 2021 *)
PROG
(PARI) {a(n) = sumdiv(n, d, d^d^2)}
(PARI) N=20; x='x+O('x^N); Vec(x*deriv(-log(prod(k=1, N, (1-x^k)^(k^(k^2-1))))))
CROSSREFS
Column k=2 of A308674.
Sequence in context: A308962 A191964 A230638 * A308670 A308571 A283719
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 16 2019
STATUS
approved

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Last modified April 15 14:37 EDT 2024. Contains 371689 sequences. (Running on oeis4.)