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.

A089098 Sign twisted convoluted convolved Fibonacci numbers H_j^(2).

Original entry on oeis.org

1, 1, 3, 5, 11, 19, 37, 65, 120, 210, 376, 654, 1149, 1985, 3443, 5911, 10159, 17345, 29605, 50305, 85400, 144516, 244272, 411900, 693729, 1166209, 1958219, 3283145, 5498595, 9197455, 15369373, 25655489, 42787456, 71293590, 118695272, 197452746, 328227725
Offset: 1

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Author

N. J. A. Sloane, Dec 05 2003

Keywords

Comments

Let "a" = the Fibonacci numbers, and "b" = the aerated Fibonacci numbers (1, 0, 1, 0, 2,...). Then A089098 = (1/2) * (a^2 + b), where a^2 = A001629, the Fibonacci numbers convolved with themselves: (1, 2, 5, 10, 20, 38,...).

Crossrefs

2nd column of A337009.

Programs

  • Maple
    with(numtheory): f := z->-1/(1-z-z^2): m := proc(r,j) d := divisors(r): W := (1/r)*z*sum(mobius(d[i])*f(z^d[i])^(r/d[i]),i=1..nops(d)): Wser := simplify(series(W,z=0,80)): coeff(Wser,z^j) end: seq(m(2,j),j=1..39);
  • Mathematica
    (1-x-x^2+x^3)/((1-x-x^2)^2*(1-x^2-x^4)) + O[x]^40 // CoefficientList[#,x]& (* Jean-François Alcover, Jan 20 2018 *)
  • PARI
    Vec(-x*(x-1)^2*(x+1)/((x^2+x-1)^2*(x^4+x^2-1)) + O(x^50)) \\ Colin Barker, Jul 23 2015

Formula

G.f.: (z/2)[1/(1-z-z^2)^2+1/(1-z^2-z^4)].
G.f.: -x*(x-1)^2*(x+1) / ((x^2+x-1)^2*(x^4+x^2-1)). - Colin Barker, Jul 23 2015

Extensions

Edited by Emeric Deutsch, Mar 06 2004