cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A153387 Decimal expansion of Sum_{n>=1} 1/Fibonacci(2*n-1).

Original entry on oeis.org

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

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Author

Eric W. Weisstein, Dec 25 2008

Keywords

Comments

Borwein et al. express the sum in terms of theta functions. - N. J. A. Sloane, May 16 2011
Duverney et al. (1997) proved that this constant is transcendental. - Amiram Eldar, Oct 30 2020

Examples

			1.8245151574069245681...
		

References

  • J. M. Borwein, D. H. Bailey and R. Girgensohn, Experimentation in Mathematics, A K Peters, Ltd., Natick, MA, 2004. x+357 pp. See pp. 202-203.

Crossrefs

Programs

  • PARI
    sumpos(n=1, 1/fibonacci(2*n-1)) \\ Michel Marcus, Feb 05 2022

Formula

Equals sqrt(5)/4 * (T(b^2)^2 - T(b)^2) where T(q) = 1 + 2*Sum_{n>=1} q^(n^2) and b = 1/2*(1-sqrt(5)); see the Arndt reference and the references cited there. - Joerg Arndt, Feb 01 2014
Equals sqrt(5) * Sum_{n>=0} (-1)^n/Lucas(2*n+1) (Carlitz, 1967). - Amiram Eldar, Feb 05 2022

Extensions

Definition reconciled to sequence and example by Clark Kimberling, Aug 06 2013