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.

A112005 Logarithmic transform of Fibonacci numbers A000045.

Original entry on oeis.org

0, 1, 0, 1, -2, 4, -17, 82, -384, 2189, -14850, 107404, -845537, 7400482, -70093256, 709888645, -7721333538, 89774204756, -1107347563761, 14456268008050, -199350032354000, 2893615098314941, -44089764970860290, 703841452185590236, -11747695951762870497
Offset: 0

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Author

Wolfdieter Lang, Sep 12 2005

Keywords

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; (t-> `if`(n=0, 0, t(n) -add(j*t(n-j)*
          binomial(n, j)*a(j), j=1..n-1)/n))(i->(<<0|1>, <1|1>>^i)[1, 2])
        end:
    seq(a(n), n=0..25);  # Alois P. Heinz, Mar 06 2018
  • Mathematica
    FullSimplify[CoefficientList[Series[Log[1 + 2*E^(x/2)*Sinh[Sqrt[5]*x/2] / Sqrt[5]], {x, 0, 20}], x] * Range[0, 20]!] (* Vaclav Kotesovec, Sep 04 2014 *)

Formula

E.g.f. log(1 + A(x)) with the e.g.f. A(x):=exp(x/2)*sinh(sqrt(5)*x/2)/(sqrt(5)/2) of A000045.
a(n) ~ -(n-1)! / r^n, where r = -1.37807491378452630283968362340785266756... is the root of the equation 2*(5-3*sqrt(5))*r + (sqrt(5)-5) * (log(5/4) + 2*log(1-coth(sqrt(5)*r/2))) = 0. - Vaclav Kotesovec, Sep 04 2014