A078975 Decimal expansion of constant C>0 such that sum(k>=1,1/C^(k^2)) = 1.

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

Offset: 1

Author

Benoit Cloitre, Jan 12 2003

Keywords

• cons
• nonn

Examples

			1.417742546...
		

Programs

Mathematica

c /. FindRoot[ EllipticTheta[3, 0, 1/c] == 3, {c, 3/2}, WorkingPrecision -> 110] // RealDigits[#, 10, 105]& // First (* Jean-François Alcover, Feb 15 2013 *)

PARI

th3(x)=1 + 2*suminf(n=1,x^n^2)
solve(x=1.4,2,th3(1/x)-3) \\ Charles R Greathouse IV, Jun 06 2016