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.

A110613 a(n+3) = 5*a(n+2) - 2*a(n+1) - 8*a(n), a(0) = 1, a(1) = 0, a(2) = 3.

Original entry on oeis.org

1, 0, 3, 7, 29, 107, 421, 1659, 6597, 26299, 105029, 419771, 1678405, 6712251, 26846277, 107379643, 429507653, 1718008763, 6871991365, 27487878075, 109951337541, 439805000635, 1759219303493, 7036875815867, 28147500467269
Offset: 0

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Author

Creighton Dement, Jul 31 2005

Keywords

Comments

A Jacobsthal related sequence (A001045). This sequence was calculated using the same rules given for A108618; the "initial seed" is the floretion given in the program code, below.

Crossrefs

Programs

  • Maple
    seriestolist(series((1-5*x+5*x^2)/((4*x-1)*(2*x-1)*(x+1)), x=0,25)); -or- Floretion Algebra Multiplication Program, FAMP Code: 2tessumseq[(.5'i - .5'k - .5i' + .5k' - .5'ij' - .5'ji' - .5'jk' - .5'kj')('i + j' + 'ij' + 'ji')] Sumtype is set to:sum[Y[15]] = sum(*) (from 3rd term, disregarding signs)
  • Mathematica
    LinearRecurrence[{5, -2, -8}, {1, 0, 3}, 50] (* G. C. Greubel, Sep 01 2017 *)
  • PARI
    x='x+O('x^50); Vec((1-5*x+5*x^2)/((4*x-1)*(2*x-1)*(x+1))) \\ G. C. Greubel, Sep 01 2017

Formula

G.f.: (1-5*x+5*x^2)/((4*x-1)*(2*x-1)*(x+1)).
Program "Superseeker" finds:
a(n) + a(n+1) = A007582(n) = A007581(n+1) - A007581(n).
a(n+2) - a(n) = A049775(n).
a(n) + 2*a(n+1) + a(n+2) = A087440(n+1).

A087439 Expansion of (1-4x)/((1-x)(1-3x)(1-5x)).

Original entry on oeis.org

1, 5, 22, 98, 451, 2135, 10312, 50468, 249061, 1235465, 6147802, 30650438, 152986471, 764135195, 3818284492, 19084248008, 95399716681, 476934013325, 2384476356382, 11921800651178, 59607259863691, 298031069141855
Offset: 0

Views

Author

Paul Barry, Sep 03 2003

Keywords

Comments

Partial sums of A081186. The sequence 0,1,5,22,.. is given by 5^n/8+3^n/4-3/8. Binomial transform of A087440.

Formula

a(n)=5*5^n/8+3*3^n/4-3/8.
Showing 1-2 of 2 results.