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A007404 Decimal expansion of Sum {n>=0} 1/2^(2^n). 17
8, 1, 6, 4, 2, 1, 5, 0, 9, 0, 2, 1, 8, 9, 3, 1, 4, 3, 7, 0, 8, 0, 7, 9, 7, 3, 7, 5, 3, 0, 5, 2, 5, 2, 2, 1, 7, 0, 3, 3, 1, 1, 3, 7, 5, 9, 2, 0, 5, 5, 2, 8, 0, 4, 3, 4, 1, 2, 1, 0, 9, 0, 3, 8, 4, 3, 0, 5, 5, 6, 1, 4, 1, 9, 4, 5, 5, 5, 3, 0, 0, 0, 6, 0, 4, 8, 5, 3, 1, 3, 2, 4, 8, 3, 9, 7, 2, 6, 5, 6, 1, 7, 5, 5, 8 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Sum_{n>=0} 1/2^(2^n) = 0.81642150902189314370...

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..20000

Boris Adamczewski, The Many Faces of the Kempner Number, Journal of Integer Sequences, Vol. 16 (2013), #13.2.15.

Simon Plouffe, Plouffe's Inverter, sum(1/2^(2^n), n=0..infinity); to 20000 digits

Simon Plouffe, sum(1/2^(2^n), n=0..infinity to 1024 digits

Jeffrey Shallit, Simple continued fractions for some irrational numbers. J. Number Theory 11 (1979), no. 2, 209-217.

MATHEMATICA

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

PROG

(PARI) { default(realprecision, 20080); x=suminf(n=0, 1/2^(2^n)); x*=10; for (n=0, 20000, d=floor(x); x=(x-d)*10; write("b007404.txt", n, " ", d)); } \\ Harry J. Smith, May 07 2009

(PARI) suminf(k = 0, 1/(2^(2^k))) \\ Michel Marcus, Mar 26 2017

CROSSREFS

Cf. A007400, A078885, A078585, A078886, A078887, A078888, A078889, A078890, A036987.

Sequence in context: A176456 A033812 A019717 * A157697 A281785 A240982

Adjacent sequences:  A007401 A007402 A007403 * A007405 A007406 A007407

KEYWORD

nonn,cons

AUTHOR

Simon Plouffe

EXTENSIONS

Edited by Robert G. Wilson v, Dec 11 2002

Deleted old PARI program Harry J. Smith, May 20 2009

STATUS

approved

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Last modified July 20 22:51 EDT 2017. Contains 289629 sequences.