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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A114431 Decimal expansion of the real solution of x^3 - x^2 - 2x - 4 = 0.

Original entry on oeis.org

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

Views

Author

Stefan Steinerberger, Feb 13 2006

Keywords

Comments

The solution of the equation is twice the value of an upper bound on randomly generated Fibonacci-like sequences.
Also, 1/log_2(x), where x is this constant, is the exponent in the exponent of the growth rate of the first Grigorchuk group. - Andrey Zabolotskiy, Apr 14 2020

Crossrefs

Cf. A114427.

Programs

  • Mathematica
    RealDigits[x/.FindRoot[x^3 - x^2 - 2x == 4, {x, 2}, WorkingPrecision -> 120], 10, 120] [[1]] (* or *) RealDigits[(1 + Surd[64 - 3 * Sqrt[417], 3] + Surd[64 + 3 * Sqrt[417], 3])/3, 10, 120][[1]] (* Harvey P. Dale, Dec 02 2017 *)
  • PARI
    default(realprecision, 105); 1/3*(1+(64-3*sqrt(417))^(1/3)+(64+3*sqrt(417))^(1/3)) \\ Michel Marcus, Jun 14 2013
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