login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A078975 Decimal expansion of constant C>0 such that sum(k>=1,1/C^(k^2)) = 1. 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 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..105.

EXAMPLE

1.417742546...

MATHEMATICA

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

PROG

(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

CROSSREFS

Sequence in context: A082455 A140657 A253635 * A050411 A010643 A108906

Adjacent sequences:  A078972 A078973 A078974 * A078976 A078977 A078978

KEYWORD

cons,nonn

AUTHOR

Benoit Cloitre, Jan 12 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 11 18:00 EDT 2021. Contains 342888 sequences. (Running on oeis4.)