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 21 results. Next

A075700 Decimal expansion of -zeta'(0).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Oct 02 2002

Keywords

Comments

The probability density function for the standard normal distribution is e^(-x^2/2 + zeta'(0)). - Rick L. Shepherd, Mar 08 2014
For every x > 0, PolyGamma(-2, x+1) - (PolyGamma(-2, x) + x*log(x) - x) equals this constant -zeta'(0), where polygamma functions of negative indices are defined for x > 0 as: PolyGamma(-1, x) = log(Gamma(x)), PolyGamma(-(n+1), x) = Integral_{t=0..x} PolyGamma(-n, x) dx, n >= 1. - Jianing Song, Apr 20 2021

Examples

			0.91893853320467274178032...
		

Crossrefs

Programs

Formula

Equals log(2*Pi)/2 = A061444/2 = log(A019727).
Equals Integral_{x=0..1} log(Gamma(x)) dx. - Jean-François Alcover, Apr 29 2013
More generally, equals t-t*log(t)+Integral_{x=t..(t+1)} log(Gamma(x)) dx for any t>=0 (the Raabe formula). - Stanislav Sykora, May 14 2015
Equals lim_{k->oo} log(k!) + k - (k + 1/2)*log(k) (by Stirling's formula). - Amiram Eldar, Aug 21 2020

Extensions

Normalized representation (leading zero and offset) R. J. Mathar, Jan 25 2009

A256127 Decimal expansion of the second Malmsten integral: Integer_{x >= 1} log(log(x))/(1 + x + x^2) dx, negated.

Original entry on oeis.org

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

Views

Author

Keywords

Examples

			-0.12632148170620903636522675325320239184424430946528...
		

Crossrefs

Cf. A115252 (first Malmsten integral), A256128 (third Malmsten integral) , A256129 (fourth Malmsten integral), A073005 (Gamma(1/3)), A256165 (log(Gamma(1/3))), A061444 (log(2*Pi)), A002391 (log 3), A002194 (sqrt 3).

Programs

  • Maple
    evalf(Pi*(8*log(2*Pi) - 3*log(3) - 12*log(GAMMA(1/3)))/(6*sqrt(3)),120); # Vaclav Kotesovec, Mar 17 2015
  • Mathematica
    RealDigits[Integrate[Log[Log[1/x]]/(1 + x + x^2), {x, 0, 1}], 10, 100][[1]] (* Alonso del Arte, Mar 16 2015 *)
    RealDigits[Pi*(8*Log[2*Pi] - 3*Log[3] - 12*Log[Gamma[1/3]])/(6*Sqrt[3]),10,105][[1]] (* Vaclav Kotesovec, Mar 17 2015 *)
  • PARI
    Pi*(8*log(2*Pi) - 3*log(3) - 12*log(gamma(1/3)))/(6*sqrt(3)) \\ Michel Marcus, Mar 18 2015
    
  • PARI
    intnum(x=0, 1, log(log(1/x))/(1 + x + x^2))
    
  • PARI
    intnum(x=1, oo, log(log(x))/(1 + x + x^2))
    
  • PARI
    intnum(x=0, [oo, 1], log(x)/(1 + 2*cosh(x))) \\ Gheorghe Coserea, Sep 26 2018

Formula

Equals Integral_{x=0..1} log(log(1/x))/(1 + x + x^2) dx.
Equals Integral_{x>=0} log(x)/(1 + 2*cosh(x)) dx.
Equals Pi*(8*log(2*Pi) - 3*log(3) - 12*log(Gamma(1/3)))/(6*sqrt(3)).

A306243 Decimal expansion of Sum_{n>=2} log(n)/n!.

Original entry on oeis.org

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

Views

Author

Rok Cestnik, Jan 31 2019

Keywords

Examples

			0.6037828627914879884...
		

Crossrefs

Programs

  • Mathematica
    NSum[Log[n]/n!, {n, 2, Infinity}, WorkingPrecision -> 110,
      NSumTerms -> 100] // RealDigits[#, 10, 100] &
  • PARI
    suminf(n=2, log(n)/n!) \\ Michel Marcus, Jan 31 2019

Formula

Equal to log(exp(1/2*log(2*exp(1/3*log(3*exp(1/4*log(4*exp(...)))))))).
Equals log(A296301). - Vaclav Kotesovec, Jun 22 2023
Equals Integral_{x=0..2*Pi} log(Gamma(x/(2*Pi))) * exp(cos(x)) * sin(x + sin(x)) dx - (e-1)*(log(2*Pi)+gamma), where gamma is Euler's constant (A001620) (Mező, 2014). - Amiram Eldar, Jan 25 2024
Equals Integral_{x=0..1} (exp(x) - 1)/(x*log(x)) - (exp(1) - 1)/log(x) dx. - Velin Yanev, Nov 29 2024

A345208 Decimal expansion of log(2*Pi) - gamma - 1, where gamma is Euler's constant (A001620).

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Jun 10 2021

Keywords

Comments

The first two formulae (in the Formula section) are similar to the sum and integral lim_{n->oo} (1/n) * Sum_{k=1..n} frac(n/k) = Integral_{x=0..1} frac(1/x) dx = 1 - gamma (A153810).
The second raw moment of the distribution of the fractional part of 1/x, where x is chosen uniformly at random from (0, 1]. Since the expected value is 1 - gamma, the second central moment, or variance, is log(2*Pi) - gamma - 1 - (1 - gamma)^2 = log(2*Pi) - gamma^2 + gamma - 2 = 0.081914807503... and the standard deviation is sqrt(log(2*Pi) - gamma^2 + gamma - 2) = 0.2862076300...

Examples

			0.26066140150781262295414738272883284868063561133564...
		

References

  • Ovidiu Furdui, Limits, Series, and Fractional Part Integrals: Problems in Mathematical Analysis, New York: Springer, 2013. See Problem 3.42, pages 145 and 195.

Crossrefs

Programs

  • Mathematica
    RealDigits[Log[2*Pi] - EulerGamma - 1, 10, 100][[1]]

Formula

Equals lim_{n->oo} (1/n) * Sum_{k=1..n} frac(n/k)^2, where frac(x) = x - floor(x) is the fractional part of x.
Equals Integral_{x=0..1} frac(1/x)^2 dx.
Equals 2 * Sum_{k>=2} (zeta(k)-1)/(k*(k+1)).
Equals A061444 - A001620 - 1.
Equals -2 * Sum_{k>=1} (H(k) - log(k) - gamma - 1/(2*k)), where H(k) = A001008(k)/A002805(k) is the k-th harmonic number (Furdui, 2013). - Amiram Eldar, Mar 26 2022

A216582 Decimal expansion of the logarithm of Pi to base 2.

Original entry on oeis.org

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

Views

Author

Alonso del Arte, Sep 09 2012

Keywords

Examples

			1.651496129472318798...
		

References

  • Jörg Arndt and Christoph Haenel, Pi Unleashed, New York: Springer (2001), p. 239.

Crossrefs

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); Log(Pi(R))/Log(2); // G. C. Greubel, Apr 08 2019
  • Maple
    evalf(log[2](Pi)) ; # R. J. Mathar, Sep 11 2012
  • Mathematica
    RealDigits[Log[2, Pi], 10, 105][[1]]
  • PARI
    log(Pi)/log(2) \\ Michel Marcus, Mar 05 2019
    
  • Sage
    log(pi,2).n(digits=100) # Jani Melik, Oct 05 2012
    

Formula

Log_2(Pi) = log(Pi) / log(2) = A053510 / A002162.
Equals (A061444 / A002162) - 1 = (A094642 / A002162) + 1. - John W. Nicholson, Mar 12 2019

A009763 a(n) is (n+1)!*(n+2)! times coefficient of x^n in (log(1-x))^-1.

Original entry on oeis.org

1, 1, 6, 76, 1620, 51780, 2310000, 136898496, 10393064640, 982930939200, 113269208976000, 15619762139984640, 2539231615282602240, 480507998223110457600, 104704722014993388288000, 26027184253285000629043200, 7320192187611052189440000000, 2312657526289162442074933248000
Offset: 0

Views

Author

Philippe Deléham, Apr 14 1997

Keywords

Comments

Related to 'logarithmic numbers'.

Crossrefs

Programs

  • Maple
    a := n -> local k; (-1)^n*(n+2)!*add(Stirling1(n+1, k)/(k+1), k = 0..n+1):
    # Or:
    ser := series(1/log(1-x), x, 20): seq((n+1)!*(n+2)!*coeff(ser, x, n), n = 0..17);
    # Peter Luschny, Jun 23 2025
  • Mathematica
    Table[(n+2)!*Abs[Sum[StirlingS1[n+1,k]/(k+1),{k,0,n+1}]],{n,0,20}] (* Vaclav Kotesovec, Aug 03 2014 *)
    a[ n_] := If[n<0, 0, (n+2)!*(n+1)!*SeriesCoefficient[ 1/x + 1/Log[1-x], {x, 0, n}]]; (* Michael Somos, Jun 21 2025 *)
  • PARI
    a(n)=local(A); if(n<0,0,n++; A=x/log(1-x+x^2*O(x^n)); n!*(n+1)!*polcoeff(A,n))

Formula

a(n) = (-1)^(n+1)*(n+1)!*(n+2)!*A002206/A002207(n).
log(2*Pi) = 1 + Sum_{n>0}{a(n)*(2n+1)/(((n+1)!)^2*n*(n+1)) = 1.83787706... = A061444. - Philippe Deléham, Jan 20 2004
Sum_{n>=0} a(n)/((n+1)*(n+1)!*(n+2)!) = Euler constant gamma = 0.5772156649... = A001620. - Philippe Deléham, Feb 26 2004
Sum_{n>0} a(n-1)/(n-1)! * x^n/n! = 1 + x/log(1-x). - Michael Somos, Jun 21 2025

Extensions

Better description and more terms from Joe Keane (jgk(AT)jgk.org), Aug 13 2002

A122914 Decimal expansion of (1 + log(2*Pi))/2, the entropy of the standard normal distribution.

Original entry on oeis.org

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

Views

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Sep 18 2006

Keywords

Comments

For a normal distribution with standard deviation sigma, add log(sigma). - Stanislav Sykora, Jan 15 2017

Examples

			1.4189385332046727417803297364056176398613974736377834128171515404827656959...
		

Crossrefs

Partial quotients in A122915.

Programs

  • Mathematica
    RealDigits[(1 + Log[2 Pi])/2, 10, 80]

Formula

Equals (1 + log(2*Pi))/2 = 1/2 - A075700 = (1 + A061444)/2.
Equals -zeta(0) - zeta'(0). - Peter Luschny, May 16 2020
Equals 1 + G'(1), where G(x) is the Barnes G-function. - Amiram Eldar, Jun 08 2022

Extensions

a(80) corrected by Georg Fischer, Jul 10 2021

A122915 Partial quotients of (1 + Log[2 Pi])/2, the entropy of the standard normal distribution.

Original entry on oeis.org

1, 2, 2, 1, 1, 2, 2, 8, 1, 8, 4, 1, 4, 1, 3, 18, 1, 7, 1, 4, 2, 4, 2, 1, 2, 1, 4, 1, 1, 17, 1, 1, 1, 23, 1, 1, 2, 28, 3, 2, 4, 1, 2, 3, 1, 39, 12, 2, 1, 1, 120, 1, 6, 1, 5, 1, 1, 1, 1, 1, 1, 4, 3, 1, 1, 5, 1, 5, 14, 1, 3, 3, 1, 5, 1, 12, 2, 7, 2, 1
Offset: 0

Views

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Sep 18 2006

Keywords

Comments

a = 1/2 - A075700; a = (1 + A061444)/2.

Crossrefs

Decimal expansion in A122914.

Programs

  • Mathematica
    ContinuedFraction[(1 + Log[2 Pi])/2, 80]

Formula

a = (1 + Log[2 Pi])/2

A248859 Decimal expansion of log(sqrt(2*Pi))/e, a constant appearing in the asymptotic expansion of (n!)^(1/n).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Mar 03 2015

Keywords

Examples

			0.3380585940662399023702794509615188742685137583402...
		

Crossrefs

Cf. A001113, A019762, A061444, A075700 (log(sqrt(2*Pi))).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); Log(2*Pi(R))/(2*Exp(1)); // G. C. Greubel, Oct 07 2018
  • Mathematica
    RealDigits[Log[Sqrt[2*Pi]]/E, 10, 105] // First
  • PARI
    log(2*Pi)/2/exp(1) \\ Charles R Greathouse IV, Apr 20 2016
    

Formula

Equals lim_{n -> infinity} (n!)^(1/n) - n/e - log(n)/(2*e).
Equals A075700/A001113 = A061444/A019762. - Amiram Eldar, Apr 12 2022

A332538 Numerators of coefficients in a series for log(2 Pi).

Original entry on oeis.org

3, 1, 1, 7, 1, 43, 79, 717, 3481, 100189, 533077, 1777722593, 156155179, 74216302403, 15537618841, 11069240202341, 5762870563187, 2682308717818019, 927089189292457, 3726882116303677517, 35762248102620751, 1529769611935770520751, 1576432862602739502061
Offset: 0

Views

Author

N. J. A. Sloane, Feb 16 2020

Keywords

Crossrefs

Cf. A061444 (log(2*Pi)).

Programs

  • Mathematica
    g[n_] := -(-1)^n*Sum[StirlingS1[n, j]/(j + 1), {j, 1, n}]/n!; Flatten[{3, Numerator[Table[Sum[g[k]*g[n + 1 - k], {k, 1, n}]/n, {n, 1, 30}]]}] (* Vaclav Kotesovec, Feb 16 2020 *)

Formula

The reference gives an explicit formula in terms of the Gregory numbers G_n = A002206/A002207.

Extensions

More terms from Vaclav Kotesovec, Feb 16 2020
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