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.

A265011 Decimal expansion of Integral_{x=0..1} sin(log(x))/((x+1)*log(x)) dx.

Original entry on oeis.org

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

Views

Author

John M. Campbell, Apr 06 2016

Keywords

Comments

This integral has an elegant evaluation in terms of the gamma function (see below formula). There is an interesting "symmetry" between the expressions involving the gamma function in this evaluation.

Examples

			This integral is equal to 0.50667090321662298198525580478358151247...
		

Crossrefs

Decimal expansions of definite integrals over elementary functions: A256127, A256128, A256129, A204067, A204068, A205885, A206161, A206160, A206769, A229174, A083648, A094691, A098687, A177218, A188141, A233382, A256273, A258086.
Cf. A309209 (continued fraction of the negation of this constant).

Programs

  • Mathematica
    Print[RealDigits[Re[Log[2] + Log[((Gamma[1 - I/2]^2 Gamma[1 + I])/(Gamma[1 + I/2]^2 Gamma[1 - I]))^(I/2)]], 10, 100]] ;
    NIntegrate[Sin[Log[x]]/(x + 1)/Log[x], {x, 0, 1}]
  • PARI
    intnum(x=0,1,sin(log(x))/(x+1)/log(x))

Formula

Equals log(2) + log(((Gamma(1 - i/2)^2*Gamma(1 + i))/(Gamma(1 + i/2)^2*Gamma(1 - i)))^(i/2)), where i = sqrt(-1) denotes the imaginary unit.
Equals Sum_{n >= 0} (-1)^n*arctan(1/(n+1)).

A204068 Decimal expansion of the Fresnel Integral Integral_{x>=0} sin(x^3) dx.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 10 2013

Keywords

Comments

Imaginary part associated with A204067.

Examples

			0.446489755784624605609282...
		

Crossrefs

Programs

  • Maple
    evalf(Pi/GAMMA(2/3)/3^(3/2) ) ;
  • Mathematica
    RealDigits[Gamma[1/3]/6, 10, 120][[1]] (* Amiram Eldar, May 26 2023 *)

Formula

Equals Pi/(Gamma(2/3)* 3^(3/2)) = A073010 / A073006.
(this value)^2 + A204067^2 = A202623^2.
Equals Gamma(1/3)/6 = A073005 / 6. - Amiram Eldar, May 26 2023

A206161 Decimal expansion of the Fresnel integral int_{x=0..infinity} cos(x^4) dx.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 10 2013

Keywords

Examples

			0.83740669676908648308360272218083226...
		

Crossrefs

Cf. A204067.

Programs

  • Maple
    evalf(Pi*cos(Pi/8)/GAMMA(3/4)/2^(3/2)) ;
  • Mathematica
    RealDigits[ Sqrt[2 + Sqrt[2]]*Gamma[1/4]/8, 10, 72] // First (* Jean-François Alcover, Feb 20 2013 *)

Formula

Equals A093954 * A144981 / A068465 .
Showing 1-3 of 3 results.