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.

A164833 Decimal expansion of Pi/8 - log(2)/2.

Original entry on oeis.org

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

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Author

Jonathan Vos Post, Aug 27 2009

Keywords

Comments

Digits and formula given at Waldschmidt, p. 4.

Examples

			0.0461254914187515000992143621808495764868961077417606...
1/(2*3*4) + 1/(6*7*8) + 1/(10*11*12) + 1/(14*15*16) + ... [_Bruno Berselli_, Mar 17 2014]
		

References

  • Mohammad K. Azarian, Problem 1218, Pi Mu Epsilon Journal, Vol. 13, No. 2, Spring 2010, p. 116. Solution published in Vol. 13, No. 3, Fall 2010, pp. 183-185.
  • L. B. W. Jolley, Summation of series, Dover Publications Inc. (New York), 1961, p. 46 (series n. 251).
  • A. J. Van Der Poorten, Effectively computable bounds for the solutions of certain Diophantine equations, Acta Arith., 33 (1977), pp. 195-207.

Crossrefs

Cf. A239362: Sum_{k>=1} 1/((3k-2)*(3k-1)*(3k)).

Programs

  • Magma
    SetDefaultRealField(RealField(130)); R:= RealField(); (Pi(R)-4*Log(2))/8; // G. C. Greubel, Aug 11 2019
    
  • Maple
    evalf[130]((Pi - 4*log(2))/8 ); # G. C. Greubel, Aug 11 2019
  • Mathematica
    Join[{0},RealDigits[Pi/8-Log[2]/2,10,120][[1]]] (* Harvey P. Dale, Nov 13 2012 *)
  • PARI
    default(realprecision, 130); (Pi - 4*log(2))/8 \\ G. C. Greubel, Aug 11 2019
    
  • Sage
    numerical_approx((pi-4*log(2))/8, digits=130) # G. C. Greubel, Aug 11 2019

Formula

Equals Sum_{n>=0} Sum_{m>=0} 1/((4*n+3)^(2*m+1)).
Equals Sum_{k>=1} 1/( (4*k-2)*(4*k-1)*(4*k) ). - Bruno Berselli, Mar 17 2014

Extensions

Normalized offset and leading zeros - R. J. Mathar, Sep 27 2009