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.

A342316 Decimal expansion of Pi/2 - log(2).

Original entry on oeis.org

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

Views

Author

Peter Luschny, Mar 14 2021

Keywords

Examples

			0.87764914623495130981408957018157487402308456532730...
		

References

  • Jean-Marie Monier, Analyse, Exercices corrigés, 2ème année MP, Dunod, 1997, Exercice 2.5.2.n, pp. 186 and 223.

Crossrefs

Cf. A019669 (Pi/2), A002162 (log(2)), A196521.

Programs

  • Mathematica
    RealDigits[N[Pi/2 - Log[2], 105]][[10]]
  • PARI
    Pi/2 - log(2) \\ Michel Marcus, Mar 14 2021

Formula

Equals (-log(4) - psi(1/4) + psi(3/4)) / 2, where psi(x) denotes the digamma function.
Equals -Integral_{x=0..1} log(x)/((1+x)*sqrt(1-x^2)) dx. - Bernard Schott, Apr 28 2021
Equals Sum_{k>=1} (-1)^(k+1)/(k*(2*k-1)). - Amiram Eldar, Jun 08 2021
From Peter Bala, Mar 05 2024: (Start)
Equals 2 * A196521.
Equals (10/3)*Integral_{x = 0..1} x/(2 - x^2*(1 - x)) dx.
Equals 5*Sum_{n >= 1} 1/(n*binomial(3*n,n)*2^n). The first 10 terms of the series gives the approximate value 0.87764914623(37...), correct to 11 decimal places. (End)