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 1-7 of 7 results.

A143298 Decimal expansion of Gieseking's constant.

Original entry on oeis.org

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

Views

Author

Eric W. Weisstein, Aug 05 2008

Keywords

Comments

The largest possible volume of a tetrahedron in hyperbolic space. Named by Adams (1998) after German mathematician Hugo Gieseking (1887 - 1915). - Amiram Eldar, Aug 14 2020

Examples

			1.0149416064096536250...
		

References

  • J. Borwein and P. Borwein, Experimental and computational mathematics: Selected writings, Perfectly Scientific Press, 2010, p. 106.
  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 233, 512.

Crossrefs

Programs

  • Maple
    sqrt(3)/6*(Psi(1,1/3)-2*Pi^2/3) ; evalf(%) ; # R. J. Mathar, Sep 23 2013
  • Mathematica
    N[(9 - PolyGamma[1, 2/3] + PolyGamma[1, 4/3])/(4*Sqrt[3]), 105] // RealDigits // First
  • PARI
    polygamma(n, x) = if (n == 0, psi(x), (-1)^(n+1)*n!*zetahurwitz(n+1, x));
    sqrt(3)/6*(polygamma(1, 1/3) - 2*Pi^2/3)
    (9 - polygamma(1, 2/3) + polygamma(1, 4/3))/(4*sqrt(3)) \\ Gheorghe Coserea, Sep 30 2018
    
  • PARI
    clausen(n, x) = my(z = polylog(n, exp(I*x))); if (n%2, real(z), imag(z));
    clausen(2, Pi/3) \\ Gheorghe Coserea, Sep 30 2018
    
  • PARI
    sqrt(3)/2 * sumpos(n=1, 1/(6*n-4)^2 + 1/(6*n-5)^2 - 1/(6*n-1)^2 - 1/(6*n-2)^2) \\ Gheorghe Coserea, Sep 30 2018

Formula

Equals (9 - PolyGamma(1, 2/3) + PolyGamma(1, 4/3))/(4*sqrt(3)).
Equals Sum_{k>0} sin(k*Pi/3)/k^2; (also equals (sqrt(3)/2)*Sum_{k>=1} -1/(6k-1)^2 - 1/(6k-2)^2 + 1/(6k-4)^2 + 1/(6k-5)^2). - Jean-François Alcover, Jun 19 2016, from the book by J. & P. Borwein.
From Amiram Eldar, Aug 14 2020: (Start)
Equals Integral_{x=0..2*Pi/3} log(2*cos(x/2)).
Equals (3*sqrt(3)/4) * (1 - Sum_{k>=0} 1/(3*k + 2)^2 + Sum_{k>=1} 1/(3*k + 1)^2) = (3*sqrt(3)/4) * Sum_{k>=1} A049347(k-1)/k^2.
Equals Pi * A244996 = Pi * log(A242710). (End)
Equals A091518/2 = A244345/5. - Hugo Pfoertner, Sep 16 2024

A122722 Number of triangulations of Delta^2 x Delta^(k-1).

Original entry on oeis.org

1, 6, 108, 4488, 376200, 58652640, 16119956160, 7519632382080, 5788821019685760, 7197150396467808000, 14206044114169232371200, 43903287397136367836697600, 210012592354755890839147008000, 1540026232221309103088828327116800, 17170286302440610680613970557956096000, 289015112280462271460535463614055526400000
Offset: 1

Views

Author

Jonathan Vos Post, Oct 22 2006

Keywords

Comments

The number of triangulations of Delta^2 x Delta^(k) is between alpha^(k^2) and beta*(k^2) where alpha = (27/16)^(1/4) ~ 1.13975 and beta = 6^(1/6) ~ 1.34800 [p. 10 of Santos's handwritten notes about "The Cayley trick"].
There are arithmetic errors in Santos's lecture notes "The Cayley trick". The same table gives lozenge tilings of k*Delta^2.
From Petros Hadjicostas, Sep 13 2019: (Start)
The first column (indexed by k) of the table on p. 9 in Santos' handwritten notes "The Cayley trick" is actually the sequence (A273464(k, k*(k-1)/2 + 1): k >= 1).
In later published papers, Santos (2004, 2005) mentions that the number of triangulations of Delta^2 x Delta^k grows as exp(A244996*k^2/2 + o(k^2)) as k -> infinity. Notice that exp(A244996 * k^2/2) = A242710^(k^2/2). [See Theorem 1 and Theorem 4.9. Probably Theorem 1, part (2), in Santos (2004) has a typo.]
Note that alpha = (27/16)^(1/4) ~ 1.13975 < A242710^(k^2/2) ~ 1.175311 < beta = 6^(1/6) ~ 1.34800 (where alpha and beta are given on the first paragraph of these comments).
The reason the name of the sequence has "Delta^2 x Delta^(k-1)" rather than "Delta^2 x Delta^k" is because (according to Santos) the number of triangulations of Delta^2 x Delta^(k-1) equals k! times the number of lozenge tilings of k*Delta^2. (End)

Examples

			a(1) = 1 * 1! = 1.
a(2) = 3 * 2! = 6.
a(3) = 18 * 3! = 108.
a(4) = "187 * 4! = 2244" [sic]; actually 187 * 4! = 4488.
a(5) = "3135 * 5! = 188100" [sic]; actually 3135 * 5! = 376200.
		

Crossrefs

Formula

Conjectures: a(n) = n! * A273464(n, n*(n+1)/2) for n >= 1; a(n) = A011555(n-1) for n >= 2. [A273464(n,k) is defined for n >= 1 and 0 <= k <= n*(n+1)/2.] - Petros Hadjicostas, Sep 12 2019

Extensions

More terms (using the references) from Petros Hadjicostas, Sep 12 2019

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.

A244997 Decimal expansion of the moment derivative W_4'(0) associated with the radial probability distribution of a 4-step uniform random walk.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 09 2014

Keywords

Examples

			0.42627839881750579092352142659616687305800676962963510754160645802652945...
		

Crossrefs

Cf. A244996.

Programs

  • Mathematica
    RealDigits[(7/2)*Zeta[3]/Pi^2, 10, 105] // First

Formula

W_4'(0) = (7/2)*zeta(3)/Pi^2.
W_4'(0) = integral over the square [0,Pi]x[0,Pi] of log(3+2*cos(x)+2*cos(y)+2*cos(x-y)) dx dy.

A245025 Decimal expansion of the moment derivative W_3'(2) associated with the radial probability distribution of a 3-step uniform random walk.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 10 2014

Keywords

Examples

			2.1422044985256634680139197847019650201206458017918000691935563806464998832...
		

Crossrefs

Cf. A244996.

Programs

  • Mathematica
    Clausen2[x_] := Im[PolyLog[2, Exp[x*I]]]; RealDigits[2 + (3/Pi)*Clausen2[Pi/3] - 3*Sqrt[3]/(2*Pi), 10, 105] // First
  • PARI
    2 + 3*imag(polylog(2, exp(Pi*I/3)))/Pi - 3*sqrt(3)/2/Pi \\ Charles R Greathouse IV, Aug 27 2014

Formula

W_3'(2) = 2 + (3/Pi)*Cl2(Pi/3) - 3*sqrt(3)/(2*Pi), where Cl2 is the Clausen function.
W_3'(2) = 2 + 3*W_3'(0) - 3*sqrt(3)/(2*Pi).

A244999 Decimal expansion of the moment derivative W_5'(0) associated with the radial probability distribution of a 5-step uniform random walk.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 09 2014

Keywords

Examples

			0.54441256175218558519587806274502767666605280202852744228702849390214369...
		

Crossrefs

Programs

  • Mathematica
    digits = 92; Log[2] - EulerGamma - NIntegrate[(BesselJ[0, x]^5 - 1)/x, {x, 0, 1}, WorkingPrecision -> digits + 20] - NIntegrate[BesselJ[0, x]^5/x, {x, 1, Infinity}, WorkingPrecision -> digits + 20] // RealDigits[#, 10, digits] & // First

Formula

W_5'(0) = log(2) - gamma - integral_{x=0..1}((J_0(x)^5-1)/x) - integral_{x>1}(J_0(x)^5/x), where J_0 is the Bessel function of the first kind.

A247447 Decimal expansion of r_(5,1), a constant which is the residue at -4 of the distribution function of the distance travelled in a 5-step uniform random walk.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Sep 17 2014

Keywords

Examples

			0.0066167302594300817140577380007496562495510327524833...
		

Crossrefs

Programs

  • Mathematica
    r[5, 0] = (2*Sqrt[15]*Re[HypergeometricPFQ[{1/2, 1/2, 1/2}, {5/6, 7/6}, 125/4]])/Pi^2; r[5, 1] = 13/225*r[5, 0] - 2/(5*Pi^4*r[5, 0]); Join[{0, 0}, RealDigits[r[5, 1], 10, 101] // First]

Formula

r_(5,1) = 13/225*r_(5,0) - 2/(5*Pi^4*r_(5,0)), where r_(5,0) is A244995 (residue at -2).
r_(5,1) = 13/(1800*sqrt(5))*Gamma(1/15)*Gamma(2/15)*Gamma(4/15)*Gamma(8/15)/Pi^4 - 1/sqrt(5)*Gamma(7/15)*Gamma(11/15)*Gamma(13/15)*Gamma(14/15)/Pi^4.
Showing 1-7 of 7 results.