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 1-3 of 3 results.

A090998 Decimal expansion of lim_{k -> +-oo} k^2*(1 - Gamma(1+i/k)) where i^2 = -1 and Gamma is the Gamma function.

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Feb 29 2004

Keywords

Comments

Limit_{k->oo} k*(1-Gamma(1+1/k)) = -Gamma'(1) = gamma = 0.577....
Decimal expansion of the higher-order exponential integral constant gamma(2,1). The higher-order exponential integrals, see A163931, are defined by E(x,m,n) = x^(n-1)*Integral_{t=x..oo} (E(t,m-1,n)/t^n) dt for m >= 1 and n >= 1, with E(x,m=0,n) = exp(-x). The series expansions of the higher-order exponential integrals are dominated by the gamma(k,n) and the alpha(k,n) constants, see A163927. - Johannes W. Meijer and Nico Baken, Aug 13 2009

Examples

			G(2,1) = 0.9890559953279725553953956515...
		

Crossrefs

Cf. A163931 (E(x,m,n)), A163927 (alpha(k,n)), A001620 (gamma).
The structure of the G(k,n=1) formulas lead (replace gamma with G and Zeta with Z) to A036039. - Johannes W. Meijer and Nico Baken, Aug 13 2009
Cf. A081855.

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); (6*EulerGamma(R)^2 + Pi(R)^2)/12; // G. C. Greubel, Feb 01 2019
    
  • Maple
    ncol:=1; nmax:=5; kmax:=nmax; for n from 1 to nmax do G(0,n):=1 od: for n from 1 to nmax do for k from 1 to kmax do G(k,n):= expand((1/k)*((gamma-sum(p^(-1),p=1..n-1))* G(k-1,n)+sum((Zeta(k-i)-sum(p^(-(k-i)),p=1..n-1))*G(i,n),i=0..k-2))) od; od: for k from 0 to kmax do G(k,ncol):=G(k,ncol) od; # Johannes W. Meijer and Nico Baken, Aug 13 2009
  • Mathematica
    RealDigits[(6*EulerGamma^2 + Pi^2)/12, 10, 104][[1]] (* Jean-François Alcover, Mar 04 2013 *)
  • PARI
    default(realprecision, 100); (6*Euler^2 +Pi^2)/12 \\ G. C. Greubel, Feb 01 2019
    
  • Sage
    numerical_approx((6*euler_gamma^2 + pi^2)/12, digits=100) # G. C. Greubel, Feb 01 2019

Formula

From Johannes W. Meijer and Nico Baken, Aug 13 2009: (Start)
G(2,1) = gamma(2,1) = gamma^2/2 + Pi^2/12.
G(k,n) = (1/k)*(gamma*G(k-1,n)) - (1/k)*Sum_{p=1..n-1} (p^(-1))* G(k-1,n) + (1/k) * Sum_{i=0..k-2} (Zeta(k-i) * G(i,n)) - (1/k)*Sum_{i=0..k-2}(Sum_{p=1..n-1} (p^(i-k)) * G(i,n)) with G(0,n) = 1 for k >= 0 and n >= 1.
G(k,n+1) = G(k,n) - G(k-1,n)/n.
GF(z,n) = GAMMA(n-z)/GAMMA(n).
(gamma - G(1,n)) = A001008(n-1)/A002805(n-1) for n >= 2. (End)
Equals A081855/2. - Hugo Pfoertner, Mar 12 2024

A261509 Decimal expansion of -Gamma'''(1).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Aug 22 2015

Keywords

Examples

			5.4448744564853177340993610041376506895716686944353825656479...
		

Crossrefs

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); L:=RiemannZeta(); EulerGamma(R)^3 + (EulerGamma(R)*Pi(R)^2)/2 + 2*Evaluate(L,3); // G. C. Greubel, Aug 30 2018
  • Mathematica
    RealDigits[EulerGamma^3 + (EulerGamma*Pi^2)/2 + 2*Zeta[3], 10, 120][[1]]
  • PARI
    default(realprecision, 100); Euler^3 + Euler*Pi^2/2 + 2*zeta(3) \\ G. C. Greubel, Aug 30 2018
    

Formula

From Amiram Eldar, Aug 06 2020: (Start)
Equals gamma^3 + gamma*Pi^2/2 + 2*zeta(3).
Equals -Integral_{x=0..oo} exp(-x)*log(x)^3 dx. (End)

A291486 Decimal expansion of Gamma''''(1).

Original entry on oeis.org

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

Views

Author

Robert G. Wilson v, Aug 24 2017

Keywords

Examples

			23.56147408402560449607312705652442040865376831336316996971897893425256...
		

Crossrefs

Cf. A000796 (Pi), A001620 (EulerGamma), A002117 (zeta(3)), A081855, A261509.

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); L:=RiemannZeta(); EulerGamma(R)^4 + EulerGamma(R)^2*Pi(R)^2 + 8*EulerGamma(R)*Evaluate(L,3) + 3*Pi(R)^4/20; // G. C. Greubel, Sep 07 2018
  • Maple
    c:= subs(x=1.0, diff(GAMMA(x), x$4)):
    evalf(c, 120);  # Alois P. Heinz, Jul 01 2023
  • Mathematica
    RealDigits[Gamma''''[1], 10, 111][[1]]
  • PARI
    default(realprecision, 100); Euler^4 + Euler^2*Pi^2 + 8*Euler*zeta(3) + 3*Pi^4/20 \\ G. C. Greubel, Sep 07 2018
    

Formula

Equals EulerGamma^4 + EulerGamma^2*Pi^2 + 8*EulerGamma*Zeta(3) + 3*Pi^4/20.
Equals Integral_{x=0..oo} exp(-x)*log(x)^4 dx. - Amiram Eldar, Aug 06 2020
Showing 1-3 of 3 results.