A215140 Decimal expansion of Sum_{n>=1} 1 / sigma(n)^n.

1, 1, 2, 7, 2, 8, 2, 0, 1, 7, 2, 8, 3, 2, 6, 5, 8, 9, 0, 3, 4, 4, 3, 7, 9, 7, 2, 3, 2, 7, 2, 5, 0, 6, 1, 3, 5, 6, 6, 1, 4, 1, 2, 3, 0, 9, 9, 8, 4, 9, 3, 1, 2, 2, 4, 5, 4, 0, 9, 6, 5, 5, 6, 2, 7, 3, 8, 6, 4, 3, 1, 9, 5, 1, 8, 1, 5, 2, 5, 9, 6, 7, 0, 6, 3, 4, 9

Offset

1,3

Links

G. C. Greubel, Table of n, a(n) for n = 1..5000

Example

1.127282017283265890344379...

Mathematica

RealDigits[N[Sum[1/DivisorSigma[1, n]^n, {n, 1, 105}], 105]][[1]]

Prog

(PARI) suminf(n=1, 1/sigma(n)^n) \\ Michel Marcus, Apr 20 2018

Crossrefs

Cf. A000203.

Sequence in context: A010697 A088666 A170854 * A278419 A197133 A178206

Adjacent sequences: A215137 A215138 A215139 * A215141 A215142 A215143

Keyword

nonn,cons

Author

Michel Lagneau, Aug 04 2012

Status

approved