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 10 results.

A229728 Decimal expansion of the square of the constant A130834.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Oct 01 2013

Keywords

Examples

			3.209912300728157678629749481779905158748592124251834494874586...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, p. 232.

Crossrefs

Programs

Formula

From Amiram Eldar, Jun 12 2023: (Start)
Equals exp(4*G/Pi) = exp(4*A006752/A000796).
Equals A097469^4. (End)

A097469 Decimal expansion of growth constant C for dimer model on square grid.

Original entry on oeis.org

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

Views

Author

Ralf Stephan, Sep 18 2004

Keywords

Examples

			1.33851515197609676693819590201851353706435369712791131464123...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Sections 1.8.3 and 5.23.1, pp. 63, 407.

Crossrefs

Cf. A000796 (Pi), A006752 (Catalan's constant).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:=RealField(); Exp(Catalan(R)/Pi(R)); // G. C. Greubel, Aug 25 2018
  • Mathematica
    RealDigits[Exp[Catalan/Pi], 10, 100][[1]] (* G. C. Greubel, Aug 25 2018 *)
  • PARI
    default(realprecision, 100); exp(Catalan/Pi) \\ G. C. Greubel, Aug 25 2018
    

Formula

Equals e^(G/Pi), with G = A006752 (Catalan's constant).
Equals exp((1/Pi^2) * Integral_{x=0..Pi/2, y=0..Pi/2} log(4*cos(x)^2 + 4*cos(y)^2) dx dy). - Vaclav Kotesovec, Jan 04 2021
Equals sqrt(A130834) = exp(A143233). - Hugo Pfoertner, Nov 18 2024

Extensions

Terms a(14) onward corrected by G. C. Greubel, Aug 26 2018

A242710 Decimal expansion of "beta", a Kneser-Mahler polynomial constant (a constant related to the asymptotic evaluation of the supremum norm of polynomials).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, May 21 2014

Keywords

Examples

			1.38135644451849779337146695685...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003; see Section 3.10, Kneser-Mahler polynomial constants, p. 232, and Section 5.23, Monomer-dimer constants, p. 408.

Crossrefs

Programs

  • Mathematica
    Exp[(PolyGamma[1, 4/3] - PolyGamma[1, 2/3] + 9)/(4*Sqrt[3]*Pi)] // RealDigits[#, 10, 100]& // First

Formula

beta = exp(G/Pi) = exp((PolyGamma(1, 4/3) - PolyGamma(1, 2/3) + 9)/(4*sqrt(3)*Pi)), where G is Gieseking's constant (cf. A143298) and PolyGamma(1,z) the first derivative of the digamma function psi(z).
Also equals exp(-Im(Li_2( 1/2 - (i*sqrt(3))/2))/Pi), where Li_2 is the dilogarithm function.

A242711 Decimal expansion of C_3, a constant related to sharp inequalities for the product of 3 polynomials, which was introduced by David Boyd.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, May 21 2014

Keywords

Examples

			1.908145626812785672415752694888439608281...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 3.10 p. 233.

Crossrefs

Cf. A130834 (C_2), A242712 (C_4), A242713 (C_5), A242714 (C_6).

Programs

  • Mathematica
    Clausen2[x_] := Im[PolyLog[2, Exp[x*I]]]; c[m_] := Exp[m/Pi*Clausen2[Pi - Pi/m]]; RealDigits[c[3], 10, 100] // First
  • PARI
    exp(3*imag(polylog(2,exp(2*I*Pi/3)))/Pi) \\ Charles R Greathouse IV, Jul 14 2014

Formula

exp(3/Pi*Clausen2(Pi - Pi/3)), where Clausen2 is Clausen's Integral.

A242712 Decimal expansion of C_4, a constant related to sharp inequalities for the product of 4 polynomials, which was introduced by David Boyd.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, May 21 2014

Keywords

Examples

			1.9484547889588356067031024668865755583...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 3.10 p. 233.

Crossrefs

Cf. A130834 (C_2), A242711 (C_3), A242713 (C_5), A242714 (C_6).

Programs

  • Mathematica
    Clausen2[x_] := Im[PolyLog[2, Exp[x*I]]]; c[m_] := Exp[m/Pi*Clausen2[Pi - Pi/m]]; RealDigits[c[4], 10, 100] // First
  • PARI
    exp(4*imag(polylog(2, exp(3*I*Pi/4)))/Pi) \\ Charles R Greathouse IV, Jul 15 2014

Formula

exp(4/Pi*Clausen2(Pi - Pi/4)), where Clausen2 is Clausen's Integral.

A242713 Decimal expansion of C_5, a constant related to sharp inequalities for the product of 5 polynomials, which was introduced by David Boyd.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, May 21 2014

Keywords

Examples

			1.967044901088071888351432414582828054693451...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 3.10 p. 233.

Crossrefs

Cf. A130834 (C_2), A242711 (C_3), A242712 (C_4), A242714 (C_6).

Programs

  • Mathematica
    Clausen2[x_] := Im[PolyLog[2, Exp[x*I]]]; c[m_] := Exp[m/Pi*Clausen2[Pi - Pi/m]]; RealDigits[c[5], 10, 100] // First
  • PARI
    exp(5*imag(polylog(2, exp(4*I*Pi/5)))/Pi) \\ Charles R Greathouse IV, Jul 15 2014

Formula

exp(5/Pi*Clausen2(Pi - Pi/5)), where Clausen2 is Clausen's Integral.

A242714 Decimal expansion of C_6, a constant related to sharp inequalities for the product of 6 polynomials, which was introduced by David Boyd.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, May 21 2014

Keywords

Examples

			1.9771268308039343866983671752539756021366...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 3.10 p. 233.

Crossrefs

Cf. A130834 (C_2), A242711 (C_3), A242712 (C_4), A242713 (C_5).

Programs

  • Mathematica
    Clausen2[x_] := Im[PolyLog[2, Exp[x*I]]]; c[m_] := Exp[m/Pi*Clausen2[Pi - Pi/m]]; RealDigits[c[6], 10, 100] // First
  • PARI
    exp(6*imag(polylog(2, exp(5*I*Pi/6)))/Pi) \\ Charles R Greathouse IV, Jul 15 2014

Formula

exp(6/Pi*Clausen2(Pi - Pi/6)), where Clausen2 is Clausen's Integral.

A378910 Decimal expansion of 2*G/Pi, where G = A006752.

Original entry on oeis.org

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

Views

Author

Stefano Spezia, Dec 10 2024

Keywords

Examples

			0.58312180806163756027676891293678983772813230797167...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 3.10, p. 232.

Crossrefs

Programs

  • Mathematica
    RealDigits[2Catalan/Pi,10,100][[1]]

Formula

Equals log(A130834).
Equals 2*A143233.

A378911 Decimal expansion of sqrt(2)*exp(2*G/Pi), where G = A006752.

Original entry on oeis.org

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

Views

Author

Stefano Spezia, Dec 10 2024

Keywords

Examples

			2.5337372794858419095832896340418632916896308088420...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 3.10, p. 233.

Crossrefs

Programs

  • Mathematica
    RealDigits[Sqrt[2]*Exp[2Catalan/Pi],10,100][[1]]

A247548 Decimal expansion of D^2, a constant associated with the "Dimer Problem" on a triangular lattice.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 19 2014

Keywords

Examples

			2.35652735334624880922914314763999476796439150067841679838661876063419126231...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 5.23 Monomer-dimer constants p. 408.

Crossrefs

Programs

  • Mathematica
    digits = 20; uv = Log[6 + 2*Cos[u] + 2*Cos[v] + 2*Cos[u + v]];
    SetOptions[NIntegrate, WorkingPrecision -> digits + 5];
    i1 = 2*NIntegrate[uv, {u, 0, Pi/2}, {v, 0, Pi/2}];
    i2 = 4*NIntegrate[uv, {u, 0, Pi/2}, {v, Pi/2, Pi}];
    i3 = 2*NIntegrate[uv, {u, -Pi, -Pi/2}, {v, Pi/2, Pi}];
    i4 = 2*NIntegrate[uv, {u, -Pi/2, 0}, {v, 0, Pi/2}];
    i5 = 4*NIntegrate[uv, {u, -Pi/2, 0}, {v, Pi/2, Pi}];
    i6 = 2*NIntegrate[uv, {u, Pi/2, Pi}, {v, Pi/2, Pi}];
    D2 = Exp[(1/(8*Pi^2))*(i1 + i2 + i3 + i4 + i5 + i6)];
    RealDigits[D2, 10, digits] // First
  • PARI
    exp(1/(8*Pi^2) * intnum(u=-Pi, Pi, intnum(v=-Pi,Pi, log(6 + 2*cos(u) + 2*cos(v) + 2*cos(u+v))))) \\ Michel Marcus, Sep 19 2014

Formula

Equals exp( 1/(8*Pi^2) * Integral_{v=-Pi..Pi} Integral_{u=-Pi..Pi} log(6 + 2*cos(u) + 2*cos(v) + 2*cos(u+v)) du dv).

Extensions

More terms from Michel Marcus, Sep 19 2014
Showing 1-10 of 10 results.