A078888 Decimal expansion of Sum {n>=0} 1/7^(2^n).

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

Offset

0,2

Links

Table of n, a(n) for n=0..104.

Aubrey J. Kempner, On Transcendental Numbers, Transactions of the American Mathematical Society, volume 17, number 4, October 1916, pages 476-482.

Index entries for transcendental numbers

Formula

Equals -Sum_{k>=1} mu(2*k)/(7^k - 1), where mu is the Möbius function (A008683). - Amiram Eldar, Jul 12 2020

Example

0.163681972716868017911...

Mathematica

RealDigits[ N[ Sum[1/7^(2^n), {n, 0, Infinity}], 110]][[1]]

Prog

(PARI) suminf(n=0, 1/7^(2^n)) \\ Michel Marcus, Nov 11 2020

Crossrefs

Cf. A165425.

Similar sums: A007404, A078885, A078585, A078886, A078887, A078889, A078890, A036987.

Sequence in context: A021615 A198937 A198867 * A293560 A021161 A137275

Adjacent sequences: A078885 A078886 A078887 * A078889 A078890 A078891

Keyword

cons,nonn

Author

Robert G. Wilson v, Dec 11 2002

Status

approved