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 1-5 of 5 results.

A005429 Apéry numbers: n^3*C(2n,n).

Original entry on oeis.org

0, 2, 48, 540, 4480, 31500, 199584, 1177176, 6589440, 35443980, 184756000, 938929992, 4672781568, 22850118200, 110079950400, 523521630000, 2462025277440, 11465007358860, 52926189069600, 242433164404200, 1102772230560000, 4984806175188840, 22404445765690560
Offset: 0

Views

Author

Keywords

References

  • S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.6.3.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Magma
    [Binomial(2*n,n)*n^3 : n in [0..30]]; // Wesley Ivan Hurt, Oct 21 2014
    
  • Mathematica
    Table[n^3 Binomial[2n,n],{n,0,30}] (* Harvey P. Dale, Apr 08 2012 *)
    CoefficientList[Series[(2*x*(2*x*(2*x+5)+1))/(1-4*x)^(7/2), {x,0,30}], x] (* Vincenzo Librandi, Oct 22 2014 *)
  • SageMath
    [n^3*binomial(2*n,n) for n in range(31)] # G. C. Greubel, Nov 19 2022

Formula

Sum_{n>=1} (-1)^(n+1) / a(n) = 2 * zeta(3) / 5.
G.f.: (2*x*(2*x*(2*x + 5) + 1))/(1-4*x)^(7/2). - Harvey P. Dale, Apr 08 2012
From Ilya Gutkovskiy, Jan 17 2017: (Start)
a(n) ~ 4^n*n^(5/2)/sqrt(Pi).
Sum_{n>=1} 1/a(n) = (1/2)*4F3(1,1,1,1; 3/2,2,2; 1/4) = A145438. (End)

Extensions

Entry revised by N. J. A. Sloane, Apr 06 2004

A261839 Decimal expansion of the central binomial sum S(5), where S(k) = Sum_{n>=1} 1/(n^k*binomial(2n,n)).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 03 2015

Keywords

Examples

			0.5054294746835192416424504819084321491886690145682628649826647...
		

Crossrefs

Cf. A073010 (S(1)), A086463 (S(2)), A145438 (S(3)), A086464 (S(4)).

Programs

  • Mathematica
    S[5] = 2*Pi*Im[PolyLog[4, (-1)^(1/3)]] + (1/9)*Pi^2*Zeta[3] - 19*Zeta[5]/3; RealDigits[S[5], 10, 103] // First
  • PARI
    suminf(n=1, 1/(n^5*binomial(2*n,n))) \\ Michel Marcus, Sep 03 2015

Formula

S(5) = 2*Pi*Im(PolyLog(4, (-1)^(1/3))) + (1/9)*Pi^2*zeta(3) -19*zeta(5)/3.
Equals (1/2) 4F3(1,1,1,1; 3/2,2,2; 1/4).
Also equals (1/(2592*sqrt(3)))*(Pi*(PolyGamma(3, 1/6) + PolyGamma(3, 1/3) - PolyGamma(3, 2/3) - PolyGamma(3, 5/6))) + (1/9)*Pi^2*zeta(3) - 19*zeta(5)/3.

A261850 Decimal expansion of the central binomial sum S(6), where S(k) = Sum_{n>=1} 1/(n^k binomial(2n,n)).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 03 2015

Keywords

Examples

			0.50267652147826928645467745997934863966460260009164...
		

Crossrefs

Cf. A073010 (S(1)), A086463 (S(2)), A145438 (S(3)), A086464 (S(4)), A261839 (S(5)), A261851 (S(7)), A261852 (S(8)).

Programs

  • Mathematica
    S[6] = Sum[1/(n^6*Binomial[2n, n]), {n, 1, Infinity}]; RealDigits[S[6], 10, 105]//First

Formula

Equals (1/2) 7F6(1,1,1,1,1,1,1; 3/2,2,2,2,2,2; 1/4).
Also equals (2/3)*Integral_{0..Pi/3} t*log(2*sin(t/2))^4 dt.

A261851 Decimal expansion of the central binomial sum S(7), where S(k) = Sum_{n>=1} 1/(n^k binomial(2n,n)).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 03 2015

Keywords

Examples

			0.501325872688178809402296710552749443726878329858...
		

Crossrefs

Cf. A073010 (S(1)), A086463 (S(2)), A145438 (S(3)), A086464 (S(4)), A261839 (S(5)), A261850 (S(6)), A261852 (S(8)).

Programs

  • Mathematica
    S[7]=-6*Pi*Im[-PolyLog[6, (-1)^(1/3)]] + (17*Pi^4*Zeta[3])/1620 + (1/3)*Pi^2*Zeta[5] - (493*Zeta[7])/24; RealDigits[S[7], 10, 105]//First

Formula

Equals (1/2) 8F7(1,...,1; 3/2,2,...,2; 1/4).
Also equals -6*Pi*Im(-PolyLog(6, (-1)^(1/3))) + (17*Pi^4*zeta(3))/1620 + (1/3)*Pi^2*zeta(5) - (493*zeta(7))/24.

A261852 Decimal expansion of the central binomial sum S(8), where S(k) = Sum_{n>=1} 1/(n^k binomial(2n,n)).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 03 2015

Keywords

Examples

			0.5006588912976705433145571270829868383840732523404540388886438...
		

Crossrefs

Cf. A073010 (S(1)), A086463 (S(2)), A145438 (S(3)), A086464 (S(4)), A261839 (S(5)), A261850 (S(6)), A261851 (S(7)).

Programs

  • Mathematica
    S[8] = Sum[1/(n^8*Binomial[2n, n]), {n, 1, Infinity}]; RealDigits[S[8], 10, 100] // First

Formula

Equals (1/2) 8F7(1,...,1; 3/2,2,...,2; 1/4).
Also equals (4/45)*Integral_{0..Pi/3} t*log(2*sin(t/2))^6 dt.
Showing 1-5 of 5 results.