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.

A344505 Decimal expansion of (exp(2*Pi) - 1) / (exp(2*Pi) + 1).

Original entry on oeis.org

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

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Author

Peter Luschny, May 22 2021

Keywords

Examples

			Approximate 0.9962720762207499442646905800...
Approximate tau/(2 + tau^2/(6 + tau^2/(10 + tau^2/(14 + tau^2/(18 + tau^2/(22 + tau^2/(26 + tau^2/(30 + ...)))))))), where tau = 2*Pi.
		

Crossrefs

Programs

  • Maple
    Digits := 100: tau := 2*Pi: (exp(tau) - 1)/(exp(tau) + 1):
    evalf(%)*10^86: ListTools:-Reverse(convert(floor(%), base, 10));
  • Mathematica
    RealDigits[Tanh[Pi], 10, 100][[1]] (* Amiram Eldar, May 22 2021 *)

Formula

Equals tanh(Pi).
Equals 1 / A175316.
Equals A175315 / A175314.
Equals 1 - 2/(1 + (Sum_{k>=0} 1/k!)^tau), where tau = 2*Pi = A019692.