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 1-2 of 2 results.

A036793 Decimal expansion of (2/Pi)*Integral_{x=0..Pi} sin(x)/x dx.

Original entry on oeis.org

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

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Author

Keywords

Comments

Integral(sin(x)/x dx) = x - x^3/(3*3!) + x^5/(5*5!) - x^7/(7*7!) + ... . - Harry J. Smith, Apr 28 2009

Examples

			1.17897974447216727..., the constant in Gibbs phenomenon.
		

References

  • E. J. Borowski and J. M. Borwein, Dictionary of Mathematics, 3rd printing, Harper Collins, 1991, Gibbs phenomenon.
  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 4.1 Gibbs-Wilbraham Constant, p. 249.

Crossrefs

Cf. A036791 (continued fraction), A061079 for Si( x ).

Programs

  • Mathematica
    RealDigits[ N[ (2/Pi)*SinIntegral[Pi], 105]][[1]] (* Jean-François Alcover, Nov 07 2012 *)
  • PARI
    { default(realprecision, 20080); y=0; x=Pi; m=x; x2=x*x; n=1; nf=1; s=1; while (x!=y, y=x; n++; nf*=n; n++; nf*=n; m*=x2; s=-s; x+=s*m/(n*nf)); x*=2/Pi; for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b036793.txt", n, " ", d)); } \\ Harry J. Smith, Apr 28 2009

Formula

A036792 divided by A019669. - R. J. Mathar, Mar 22 2011

A127756 Row sums of the inverse of number triangle A(n,k) = 1/n! if k <= n <= 2k, 0 otherwise.

Original entry on oeis.org

1, 1, 1, 5, 18, 97, 600, 4325, 35280, 322578, 3265920, 36288097, 439084800, 5748019800, 80951270400, 1220496081125, 19615115520000, 334764638243280, 6046686277632000, 115242726703426578
Offset: 0

Views

Author

Paul Barry, Jan 28 2007

Keywords

Comments

Row sums of A127755. a(2n) = A061079(n), n > 0.
Showing 1-2 of 2 results.