A258716 Decimal expansion of 3 + 2*Sum_{k>=0} 1/Product_{i=0..k} (2^(2^i) - 1).

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

Offset

1,1

Links

Table of n, a(n) for n=1..80.

Gary W. Adamson and N. J. A. Sloane, Correspondence, May 1994, including Adamson's MSS "Algorithm for Generating nth Row of Pascal's Triangle, mod 2, from n", and "The Tower of Hanoi Wheel". Defines this number.

Formula

Equals 3 + A258715.

From Amiram Eldar, Feb 19 2024: (Start)

Equals 2 * A258714 + 3.

Equals 2/A215016. (End)

Example

5.7112854057096334466665254291814791046797658771989754...

Mathematica

RealDigits[2/NProduct[1 - 1/2^(2^k), {k, 0, Infinity}, WorkingPrecision -> 120]][[1]] (* Amiram Eldar, Feb 19 2024 *)

Prog

(PARI) 2/prodinf(k = 0, 1 - 1/2^(2^k)) \\ Amiram Eldar, Feb 19 2024

Crossrefs

Cf. A215016, A258714, A258715.

Sequence in context: A111833 A011378 A329346 * A195300 A019697 A217173

Adjacent sequences: A258713 A258714 A258715 * A258717 A258718 A258719

Keyword

nonn,cons

Author

N. J. A. Sloane, Jun 15 2015

Status

approved