A340841 Decimal expansion of Sum_{n>=0} 1/(n*2^n + 1).

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

Offset

1,2

Comments

This constant is the sum of reciprocals of Cullen numbers.

Links

Table of n, a(n) for n=1..88.

Formula

Equals Sum_{n>=0} 1/A002064(n).

Example

1.5106374481309548528461974960802456940320940529869241186970756482342266...

Mathematica

First[RealDigits[NSum[1/(n*2^n+1), {n, 0, Infinity}, NSumTerms -> 100, Method -> {"NIntegrate", "MaxRecursion" -> 10}, WorkingPrecision -> 100]]] (* Stefano Spezia, Jan 24 2021 *)

Prog

(PARI) suminf(n=0, 1/(n*2^n + 1)) \\ Michel Marcus, Jan 24 2021

Crossrefs

Cf. A002064.

Sequence in context: A019904 A002068 A021666 * A143148 A198541 A200420

Adjacent sequences: A340838 A340839 A340840 * A340842 A340843 A340844

Keyword

nonn,cons

Author

Marco Ripà, Jan 23 2021

Status

approved