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.

A107458 Expansion of g.f.: (1-x^2-x^3)/( (1+x)*(1-x-x^3) ).

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 1, 1, 2, 2, 4, 5, 8, 11, 17, 24, 36, 52, 77, 112, 165, 241, 354, 518, 760, 1113, 1632, 2391, 3505, 5136, 7528, 11032, 16169, 23696, 34729, 50897, 74594, 109322, 160220, 234813, 344136, 504355, 739169, 1083304, 1587660, 2326828, 3410133, 4997792, 7324621
Offset: 0

Views

Author

N. J. A. Sloane, Mar 08 2008

Keywords

Comments

The sequence can be interpreted as the top-left entry of the n-th power of a 4 X 4 (0,1) matrix. There are 12 different choices (out of 2^16) for that (0,1) matrix. - R. J. Mathar, Mar 19 2014

Crossrefs

Programs

  • GAP
    a:=[1,0,0,0];; for n in [5..50] do a[n]:=a[n-2]+a[n-3]+a[n-4]; od; a; # G. C. Greubel, Jan 03 2020
  • Haskell
    a107458 n = a107458_list !! n
    a107458_list = 1 : 0 : 0 : 0 : zipWith (+) a107458_list
       (zipWith (+) (tail a107458_list) (drop 2 a107458_list))
    -- Reinhard Zumkeller, Mar 23 2012
    
  • Magma
    R:=PowerSeriesRing(Integers(), 50); Coefficients(R!(1-x^2-x^3)/( (1+x)*(1-x-x^3))); // Marius A. Burtea, Jan 02 2020
    
  • Maple
    seq(coeff(series( (1-x^2-x^3)/( (1+x)*(1-x-x^3) ), x, n+1), x, n), n = 0..50); # G. C. Greubel, Jan 03 2020
  • Mathematica
    CoefficientList[Series[(1-x^2-x^3)/(1-x^2-x^3-x^4),{x,0,50}],x] (* or *) LinearRecurrence[{0,1,1,1},{1,0,0,0},50] (* Harvey P. Dale, Jun 20 2011 *)
  • PARI
    my(x='x+O('x^50)); Vec((1-x^2-x^3)/((1+x)*(1-x-x^3))) \\ G. C. Greubel, Apr 27 2017
    
  • Sage
    def A107458_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( (1-x^2-x^3)/((1+x)*(1-x-x^3)) ).list()
    A107458_list(50) # G. C. Greubel, Jan 03 2020
    

Formula

a(n) = a(n-2) + a(n-3) + a(n-4); a(0)=1, a(1)=0, a(2)=0, a(3)=0. - Harvey P. Dale, Jun 20 2011
a(n) + a(n-1) = A000930(n-4). - R. J. Mathar, Mar 19 2014