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.

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A357053 Decimal expansion of Sum_{k>=1} k/Fibonacci(2*k).

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Sep 10 2022

Keywords

Comments

This constant is transcendental (Duverney et al., 1998).

Examples

			2.39741418791652120040922449568177870852072229637554...
		

References

  • Daniel Duverney, Keiji Nishioka, Kumiko Nishioka, and Iekata Shiokawa, Transcendence of Jacobi's theta series and related results, in: K. Györy, et al. (eds.), Number Theory, Diophantine, Computational and Algebraic Aspects, Proceedings of the International Conference held in Eger, Hungary, July 29-August 2, 1996, de Gruyter, 1998, pp. 157-168.

Crossrefs

Programs

  • Mathematica
    RealDigits[Sum[k/Fibonacci[2*k], {k, 1, 300}], 10, 100][[1]]
  • PARI
    sumpos(k=1, k/fibonacci(2*k)) \\ Michel Marcus, Sep 10 2022

Formula

Equals Sum_{k>=1} k/A001906(k).
Equals sqrt(5) * Sum_{k>=1} 1/Lucas(2*k-1)^2 (Jennings, 1994).
Equals (1/2)*(1/phi^4 - 1)*theta_4'(1/phi^2)/theta_4(1/phi^2), where phi is the golden ratio (A001622) and theta_4 is a Jacobi theta function.

A357054 Decimal expansion of Sum_{k>=1} (-1)^(k+1)*k/Fibonacci(2*k).

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Sep 10 2022

Keywords

Examples

			0.58000473950777068006747098189552280269850126096461...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Sum[(-1)^(k+1)*k/Fibonacci[2*k], {k, 1, 300}], 10, 100][[1]]
  • PARI
    sumalt(k=1, (-1)^(k+1)*k/fibonacci(2*k)) \\ Michel Marcus, Sep 10 2022

Formula

Equals Sum_{k>=1} (-1)^(k+1)*k/A001906(k).
Equals (1/sqrt(5)) * Sum_{k>=1} 1/Fibonacci(2*k-1)^2 (Jennings, 1994).

A346588 Decimal expansion of the sum of reciprocals of tribonacci numbers A000213.

Original entry on oeis.org

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

Views

Author

Christoph B. Kassir, Jul 24 2021

Keywords

Examples

			3.7739480601970158183854024266295127497680741732225...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Total[1/LinearRecurrence[{1, 1, 1}, {1, 1, 1}, 500]], 10, 105][[1]] (* Amiram Eldar, Jul 26 2021 *)

Extensions

More terms from Jon E. Schoenfield, Jul 25 2021
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