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.

A009435 Expansion of e.g.f.: log(1+x)/cosh(x).

Original entry on oeis.org

0, 1, -1, -1, 0, 29, -105, 139, -2072, 31737, -247545, 1824151, -22456104, 313750293, -3929185169, 51584719523, -793292190480, 13137192234225, -221862616530705, 3947317975733039, -75492532592047280, 1522475446731094285
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 30);
    [0] cat Coefficients(R!(Laplace( Log(1+x)/Cosh(x) ))); // G. C. Greubel, Sep 06 2023
    
  • Mathematica
    With[{nn=30},CoefficientList[Series[Log[1+x]/Cosh[x],{x,0,nn}],x] Range[ 0,nn]!] (* Harvey P. Dale, Oct 01 2014 *)
  • PARI
    my(x='x+O('x^30)); concat([0],Vec(serlaplace(log(1+x)/cosh(x)))) \\ Joerg Arndt, Sep 06 2023
  • SageMath
    def A009435_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P( log(1+x)/cosh(x) ).egf_to_ogf().list()
    A009435_list(40) # G. C. Greubel, Sep 06 2023
    

Formula

a(n) ~ (-1)^(n+1) * (n-1)! / cosh(1). - Vaclav Kotesovec, Oct 01 2014

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997
Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Oct 01 2014

A009437 Expansion of e.g.f. log(1+x)/exp(sinh(x)).

Original entry on oeis.org

0, 1, -3, 8, -28, 119, -581, 3345, -22352, 170889, -1480881, 14361885, -154177068, 1814792589, -23230500541, 321160966833, -4767464107904, 75612375796689, -1275789176648193, 22815192314465685, -431023517858496044
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 30);
    [0] cat Coefficients(R!(Laplace( Log(1+x)*Exp(-Sinh(x)) ))); // G. C. Greubel, Sep 08 2023
    
  • Mathematica
    With[{nn=20},CoefficientList[Series[Log[1+x]/Exp[Sinh[x]],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Oct 01 2013 *)
  • SageMath
    def A009437_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P( log(1+x)*exp(-sinh(x)) ).egf_to_ogf().list()
    A009437_list(31) # G. C. Greubel, Sep 08 2023

Formula

a(n) ~ (n-1)! * (-1)^(n+1) * exp(sinh(1)). - Vaclav Kotesovec, Jan 23 2015

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997
Definition clarified by Harvey P. Dale, Oct 01 2013
Showing 1-2 of 2 results.