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.

Previous Showing 11-16 of 16 results.

A228043 Decimal expansion of sum of reciprocals, row 5 of Wythoff array, W = A035513.

Original entry on oeis.org

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

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Author

Clark Kimberling, Aug 05 2013

Keywords

Comments

Let c be the constant given by A079586, that is, the sum of reciprocals of the Fibonacci numbers F(k) for k>=1. The number c-1, the sum of reciprocals of row 1 of W, is known to be irrational (see A079586). Conjecture: the same is true for all the other rows of W.
Let h be the constant given at A153387 and s(n) the sum of reciprocals of numbers in row n of W. Then h < 1 + s(n)*floor(n*tau) < c. Thus, s(n) -> 0 as n -> oo.

Examples

			1/12 + 1/20 + 1/32 + ... = 0.21497141656079438829300282572973179492222...
		

Crossrefs

Programs

  • Mathematica
    f[n_] := f[n] = Fibonacci[n]; g = GoldenRatio; w[n_, k_] := w[n, k] = f[k + 1]*Floor[n*g] + f[k]*(n - 1);
    n = 5; Table[w[n, k], {n, 1, 5}, {k, 1, 5}]
    r = N[Sum[1/w[n, k], {k, 1, 2000}], 120]
    RealDigits[r, 10]

Formula

Equals A079586/4 - 5/8. - Amiram Eldar, May 22 2021

A371647 Decimal expansion of Sum_{k>=0} 1/Fibonacci(5^k).

Original entry on oeis.org

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

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Author

Amiram Eldar, Mar 31 2024

Keywords

Comments

This constant is a transcendental number (Nyblom, 2001).

Examples

			1.20001332889036987670776409546835505643055506881380...
		

Crossrefs

Similar constants: A079585, A079586, A153386, A153387, A371649.

Programs

  • Mathematica
    RealDigits[Sum[1/Fibonacci[5^k], {k, 0, 10}], 10, 120][[1]]
  • PARI
    suminf(k = 0, 1/fibonacci(5^k))

Formula

Equals Sum_{k>=0} 1/A145232(k).

A079587 Continued fraction expansion of Sum_{k>=1} 1/F(k) where F(k) is the k-th Fibonacci number A000045(k).

Original entry on oeis.org

3, 2, 1, 3, 1, 1, 13, 2, 3, 3, 2, 1, 1, 6, 3, 2, 4, 362, 2, 4, 8, 6, 30, 50, 1, 6, 3, 3, 2, 7, 2, 3, 1, 3, 2, 1, 1, 1, 1, 3, 4, 1, 1, 1, 172, 3, 26, 1, 18, 8, 2, 1, 1, 2, 8, 2, 72, 2, 3, 1, 1, 1, 1, 5, 2, 33, 1, 2, 52, 1, 3, 5, 1, 11, 1, 1, 3, 13, 2, 2, 4, 2, 14, 4, 1, 1, 10, 4, 4, 3, 5, 17, 3, 4, 2, 4, 1
Offset: 0

Views

Author

Benoit Cloitre, Jan 26 2003

Keywords

Examples

			3.35988566624....
		

Crossrefs

Cf. A079586 (decimal expansion), A153386, A153387.

Extensions

Offset changed by Andrew Howroyd, Jul 06 2024

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
Previous Showing 11-16 of 16 results.