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.

Showing 1-10 of 12 results. Next

A255685 Decimal expansion of the alternating double sum U(3,1) = Sum_{i>=2} (Sum_{j=1..i-1} (-1)^(i+j)/(i^3*j)) (negated).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Mar 02 2015

Keywords

Examples

			-0.117875999650509326841013950834137618715217513175975...
		

Crossrefs

Cf. A099218.

Programs

  • Mathematica
    U[3,1] = Pi^4/180 + (Pi^2/12)*Log[2]^2  - (1/12)*Log[2]^4 - 2*PolyLog[4, 1/2]; RealDigits[U[3,1], 10, 103] // First
  • PARI
    Pi^4/180 + (Pi^2/12)*log(2)^2  - (1/12)*log(2)^4 - 2*polylog(4, 1/2) \\ Gheorghe Coserea, Sep 30 2018

Formula

Pi^4/180 + (Pi^2/12)*log(2)^2 - (1/12)*log(2)^4 - 2*Li_4(1/2).

A099217 Decimal expansion of Li_3(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Examples

			0.537213193608040200940623225594965826670402499340...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 1.6.3, p. 44.
  • L. Lewin, Polylogarithms and associated Functions, North Holland (1981) A.2.6(3)

Crossrefs

Programs

Formula

Li_3(1/2) = Sum_{k>0} 1/(2^k*k^3) = 0.537213193608...
Li_3(1/2) = 7*zeta(3)/8-Pi^2*log(2)/12+log(2)^3/6. - Benoit Cloitre, May 22 2006

Extensions

Leading zero removed by R. J. Mathar, Feb 05 2009

A099219 Decimal expansion of Li_5(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Examples

			0.50840057924...
		

References

  • Alexander Apelblat, Tables of Integrals and Series, Harri Deutsch (1996), Section 1.3.2.

Crossrefs

Programs

Formula

Li_5(1/2) = Sum_{k>0} 1/2^k/k^5.

A099220 Decimal expansion of Li_6(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Crossrefs

Programs

Formula

Li_6(1/2)=sum(k>0, 1/2^k/k^6)=0.5040953978...

A099221 Decimal expansion of Li_7(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Crossrefs

Programs

Formula

Li_7(1/2)=sum(k>0, 1/2^k/k^7)=0.50201456332470849456....

Extensions

Formula value corrected and leading zero removed by R. J. Mathar, Feb 05 2009

A099222 Decimal expansion of Li_8(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Crossrefs

Programs

Formula

Li_8(1/2)=sum(k>0, 1/2^k/k^8)=0.500996659...

A099223 Decimal expansion of Li_9(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Crossrefs

Programs

Formula

Li_9(1/2)=sum(k>0, 1/2^k/k^9)=0.5004948881...

A099224 Decimal expansion of Li_{10}(1/2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 06 2004

Keywords

Crossrefs

Programs

Formula

Li_{10}(1/2)=sum(k>0, 1/2^k/k^10)=0.500246320606006775...

A074903 Decimal expansion of the mean number of iterations in comparing two numbers via their continued fractions.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Sep 15 2002

Keywords

Comments

Another description: Decimal expansion of the mean number of comparisons (moment sum of index 2) in the basic continued fraction sign algorithm ("BCF-sign").
Still another description: Decimal expansion of expected number of iterations of Gaussian reduction of a 2-dimensional lattice.

Examples

			1.351131574491659001793868005256521068360651508742701687345147211...
(Only the first 31 digits are the same as those given by Flajolet & Vallée. - _Jean-François Alcover_, Apr 23 2015)
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, page 161.
  • Philippe Flajolet and Brigitte Vallée, Continued fraction algorithms and constants, in "Constructive, Experimental, and Nonlinear Analysis", Michel Théra Editor, CMS Conference Proceedings, Canadian Mathematical Society Volume 27 (2000), p. 67.

Crossrefs

Cf. A099218.

Programs

  • Mathematica
    17 - 60/Pi^4 (24*PolyLog[4, 1/2] - Pi^2*Log[2]^2 + 21*Zeta[3]*Log[2] + Log[2]^4) // RealDigits[#, 10, 100]& // First (* Jean-François Alcover, Mar 19 2013, after Steven Finch *)
  • PARI
    17 - 60*(24*polylog(4, 1/2) - Pi^2*log(2)^2 + 21*zeta(3)*log(2) + log(2)^4)/Pi^4 \\ Charles R Greathouse IV, Aug 27 2014

Formula

Equals (-60/Pi^4)*(24*Li_4(1/2) - Pi^2*log(2)^2 + 21*zeta(3)*log(2) + log(2)^4) + 17, with Li_4 the tetralogarithm function. - Jean-François Alcover, Apr 23 2015

Extensions

Corrected and extended by Jean-François Alcover, Mar 19 2013
Entry revised by N. J. A. Sloane, Apr 24 2015 to include information from two other entries (submitted respectively by Eric W. Weisstein, Aug 05 2008 and Jean-François Alcover, Apr 23 2015) that formerly described this same constant.

A214508 Decimal expansion of the series limit sum_{k>=1} (-1)^(k+1) sum_{t=1..k} 1/(t^2*(k+1)^2).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jul 19 2012

Keywords

Comments

Equals the alternating sum over (-1)^(k+1)*H_k^(2)/(k+1)^2, where H_k^(2) is the harmonic sum over inverse squares, H_k^(2) = sum_{t=1..k} 1/t^2 = 1, 5/4, 49/36, 205/144, 5269/3600,..., see A007406. The sum over H_k^(2)/(k+1)^2, over the absolute values, is Pi^4/120 = 0.811742425283353...

Examples

			0.162654667397420080...
		

Programs

  • Maple
    a099218 := polylog(4,1/2) ;
    -4*a099218+13*Pi^4/288-7/2*Zeta(3)*log(2)+Pi^2/6*(log(2))^2-(log(2))^4/6 ;
    evalf(%) ;
  • Mathematica
    NSum[(-1)^(k + 1)*HarmonicNumber[k, 2]/(k + 1)^2, {k, 1, Infinity}, Method -> "AlternatingSigns", WorkingPrecision -> 110] // RealDigits[#, 10, 105] & // First (* or, from formula: *) 13*Pi^4/288 + 1/6*Pi^2*Log[2]^2 - 1/6*Log[2]*(Log[2]^3 + 21*Zeta[3]) - 4*PolyLog[4, 1/2] // RealDigits[#, 10, 105]& // First (* Jean-François Alcover, Mar 06 2013 *)
  • PARI
    13*Pi^4/288 + 1/6*Pi^2*log(2)^2 - 1/6*log(2)*(log(2)^3 + 21*zeta(3)) - 4*polylog(4, 1/2) \\ Charles R Greathouse IV, Jul 18 2014

Formula

Equals -4*A099218 +13*Pi^4/288 -7*A002117*log(2)/2+log^2(2)*(Pi^2-log^2(2))/6.

Extensions

More terms from Jean-François Alcover, Feb 12 2013
Showing 1-10 of 12 results. Next