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.

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A257436 Decimal expansion of G(1/3), a generalized Catalan constant.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Apr 23 2015

Keywords

Examples

			0.855389245838564640972481036740456552226831197315573480398142...
		

Crossrefs

Cf. A006752 (G(0) = Catalan), A257435 (G(1/6)), A091648 (G(1/4)), A257437 (G(1/12)), A257438 (G(1/5)).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); (3/8)*Sqrt(3)*Log(2 + Sqrt(3)); // G. C. Greubel, Aug 24 2018
  • Mathematica
    RealDigits[(3/8)*Sqrt[3]*Log[2 + Sqrt[3]], 10, 107] // First
    N[Pi*HypergeometricPFQ[{1/6, 1/2, 5/6}, {1, 3/2}, 1]/4, 105] (* Vaclav Kotesovec, Apr 24 2015 *)
  • PARI
    (3/8)*sqrt(3)*log(2 + sqrt(3)) \\ G. C. Greubel, Aug 24 2018
    

Formula

G(s) = (Pi/4) * 3F2(1/2, 1/2-s, s+1/2; 1, 3/2; 1), with 2F1 the hypergeometric function.
G(s) = (1/(8*s))*(Pi + cos(Pi*s)*(psi(1/4+s/2) - psi(3/4+s/2))), where psi is the digamma function (PolyGamma).
G(1/3) = (3/8)*sqrt(3)*log(2 + sqrt(3)) = (3/4)*sqrt(3)*arccoth(sqrt(3)).

A257437 Decimal expansion of G(1/12), a generalized Catalan constant.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Apr 23 2015

Keywords

Examples

			0.91205508937271840001882865569309753445114291198031874684362426...
		

Crossrefs

Cf. A006752 (G(0) = Catalan), A257435 (G(1/6)), A091648 (G(1/4)), A257436 (G(1/3)), A257438 (G(1/5)).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); 3*(Sqrt(3)+1)*(Log(Sqrt(2)-1) + (Sqrt(3)/2)*Log(Sqrt(3)+ Sqrt(2))) // G. C. Greubel, Aug 24 2018
  • Mathematica
    RealDigits[3*(Sqrt[3]+1)*(Log[Sqrt[2]-1] + (Sqrt[3]/2)*Log[Sqrt[3]+ Sqrt[2]]), 10, 103] // First
    N[Pi*HypergeometricPFQ[{5/12, 1/2, 7/12}, {1, 3/2}, 1]/4, 106] (* Vaclav Kotesovec, Apr 24 2015 *)
  • PARI
    3*(sqrt(3)+1)*(log(sqrt(2)-1) + (sqrt(3)/2)*log(sqrt(3)+ sqrt(2))) \\ G. C. Greubel, Aug 24 2018
    

Formula

G(s) = (Pi/4) * 3F2(1/2, 1/2-s, s+1/2; 1, 3/2; 1), with 2F1 the hypergeometric function.
G(s) = (1/(8*s))*(Pi + cos(Pi*s)*(psi(1/4+s/2) - psi(3/4+s/2))), where psi is the digamma function (PolyGamma).
G(1/12) = 3*(sqrt(3)+1)*(log(sqrt(2)-1) + (sqrt(3)/2)*log(sqrt(3)+sqrt(2))).

A257438 Decimal expansion of G(1/5), a generalized Catalan constant.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Apr 23 2015

Keywords

Examples

			0.8936714234609635543020698545835460075475580947963280782203...
		

Crossrefs

Cf. A006752 (G(0) = Catalan), A257435 (G(1/6)), A091648 (G(1/4)), A257436 (G(1/3)), A257437 (G(1/12)).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); (5/8)*Sqrt(5+2*Sqrt(5))*(((Sqrt(5)-1)/2)*Argsinh(Sqrt(5+2*Sqrt(5))) - Argsinh(Sqrt(5-2*Sqrt(5)))); // G. C. Greubel, Aug 24 2018
  • Mathematica
    RealDigits[(5/8)*Sqrt[5+2*Sqrt[5]]*(((Sqrt[5]-1)/2)*ArcSinh[Sqrt[5+2*Sqrt[5]]] - ArcSinh[Sqrt[5-2*Sqrt[5]]]), 10, 104] // First
    N[Pi*HypergeometricPFQ[{3/10, 1/2, 7/10}, {1, 3/2}, 1]/4, 105] (* Vaclav Kotesovec, Apr 24 2015 *)
  • PARI
    (5/8)*sqrt(5+2*sqrt(5))*(((sqrt(5)-1)/2)*asinh(sqrt(5 +2*sqrt(5))) - asinh(sqrt(5-2*sqrt(5)))) \\ G. C. Greubel, Aug 24 2018
    

Formula

G(s) = (Pi/4) * 3F2(1/2, 1/2-s, s+1/2; 1, 3/2; 1), with 2F1 the hypergeometric function.
G(s) = (1/(8*s))*(Pi + cos(Pi*s)*(psi(1/4+s/2) - psi(3/4+s/2))), where psi is the digamma function (PolyGamma).
G(1/5) = (5/8)*sqrt(5+2*sqrt(5))*(((sqrt(5)-1)/2)*arcsinh(sqrt(5+2*sqrt(5))) - arcsinh(sqrt(5-2*sqrt(5)))).

A245592 Decimal expansion of the Ising constant K_c, the ratio of the coupling constant to the ferromagnetic critical temperature, in the two-dimensional case.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 30 2014

Keywords

Examples

			0.4406867935097715126163046624898961545140801641308177053766478...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.22 Lenz-Ising Constants, p. 396.

Crossrefs

Cf. A091648.

Programs

  • Mathematica
    RealDigits[(1/2)*Log[1 + Sqrt[2]], 10, 102] // First

Formula

K_c = (1/2)*log(1 + sqrt(2)) = (1/2)*A091648.
Equals Integral_{0..1} x/sqrt(1 + x^4) dx. - Peter Bala, Oct 28 2019
Equals arcsinh(1)/2. - Peter Luschny, Oct 29 2019
Equals arctanh(sqrt(2)-1). - Amiram Eldar, Feb 09 2024

A093754 Decimal expansion of -Catalan + (Pi*arcsinh(1))/2 + HypergeometricPFQ[{1/2, 1, 1}, {3/2, 3/2}, 1/9]/6.

Original entry on oeis.org

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

Views

Author

Eric W. Weisstein, Apr 15 2004

Keywords

Examples

			0.63951035187031100196269308542732367987599462518472...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[-Catalan + (Pi*ArcSinh[1])/2 + HypergeometricPFQ[{1/2, 1, 1}, {3/2, 3/2}, 1/9]/6, 10, 100][[1]] (* Amiram Eldar, Apr 12 2022 *)

Formula

Equals Integral_{x=0..1, y=0..1} 1/(x^2 + y^2 + 1) dy dx.
Equals Integral_{x=0..1} arccot(sqrt(x^2+1))/sqrt(x^2+1) dx. - Amiram Eldar, Apr 12 2022

Extensions

Keyword:cons added by R. J. Mathar, Apr 01 2010

A129269 Decimal expansion of arcsinh(1/5).

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Jul 27 2008

Keywords

Examples

			0.19869011034924140647463691595020696822130879422445377302126...
		

Crossrefs

Decimal expansion of arcsinh(1/k): A091648 (k=1), A002390 (k=2), A129187(k=3), A129200 (k=4).

Programs

A157700 Decimal expansion of log(4/(1 + sqrt(2))).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Mar 04 2009

Keywords

Comments

Equals Sum_{n>=2, n even} binomial(2n,n)/(n*4^n) = A016627-A091648.

Examples

			0.5049207741003475936018...
		

Programs

  • Magma
    SetDefaultRealField(RealField(100)); Log(4/(1+Sqrt(2))); // G. C. Greubel, Oct 02 2018
  • Maple
    log(4/(1+sqrt(2))) ;
  • Mathematica
    RealDigits[Log[4/(1+Sqrt[2])],10,120][[1]] (* Harvey P. Dale, Jun 08 2014 *)
  • PARI
    default(realprecision, 100); log(4/(1+sqrt(2))) \\ G. C. Greubel, Oct 02 2018
    

A169800 Decimal expansion of 2/log(1+sqrt(2)).

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, May 18 2010

Keywords

Comments

Critical temperature for two-dimensional Ising model.

Examples

			2.2691853142130219681144908103065724757259815855040013500506...
		

Crossrefs

Cf. A091648 (log(1 + sqrt(2))).

Programs

A293812 Decimal expansion of log(3)/log(1 + sqrt(2)).

Original entry on oeis.org

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

Views

Author

Arkadiusz Wesolowski, Oct 16 2017

Keywords

Comments

Fractal dimension of the frontier of the Fibonacci word fractal.

Examples

			1.24647743572981584189100424874815183996105530003376417796845193354456...
		

Crossrefs

Equals A002391 / A091648.

Programs

  • Magma
    SetDefaultRealField(RealField(105)); n:=Log(1+Sqrt(2),3); Reverse(Intseq(Floor(10^104*n)));
    
  • Maple
    evalf(log(3)/log(1+sqrt(2)),110); # Muniru A Asiru, Oct 11 2018
  • Mathematica
    RealDigits[Log[3]/Log[1 + Sqrt[2]], 10, 100][[1]] (* G. C. Greubel, Oct 10 2018 *)
  • PARI
    log(3)/log(1+sqrt(2))

A354633 Decimal expansion of the negated digamma function at 3/8.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jun 01 2022

Keywords

Examples

			psi(3/8) = -2.7539990491451...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[PolyGamma[3/8], 10, 100][[1]] (* Amiram Eldar, Jun 03 2022 *)

Formula

Equals sqrt(2)*arcsinh(1) - 4*log(2) - (sqrt(2)-1)*Pi/2 - gamma, where gamma is Euler's constant (A001620). - Amiram Eldar, Jun 03 2022
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