A211878 Decimal expansion of positive constant C such that 1 = Sum_{k>=1} 1/C^(2^k).

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

Offset: 1

Author

Jimmy Zotos and Balarka Sen, Feb 13 2013

Keywords

• cons
• nonn

Examples

			C = 1.3290591087495595646...
		

Programs

Maple

Digits:= 120:
s:= convert(fsolve(sum(1/C^(2^k), k=1..infinity)=1, C=1)/10, string):
seq(parse(s[n+1]), n=1..112);

Mathematica

digits = 112; f[x_?NumericQ] := NSum[1/x^(2^k), {k, 1, Infinity}, WorkingPrecision -> digits]; x /. FindRoot[f[x] == 1, {x, 3/2, 1, 2}, WorkingPrecision -> digits] // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Feb 20 2014 *)

Extensions

More terms from Alois P. Heinz, Feb 13 2013