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.

A016208 Expansion of 1/((1-x)*(1-3*x)*(1-4*x)).

Original entry on oeis.org

1, 8, 45, 220, 1001, 4368, 18565, 77540, 320001, 1309528, 5326685, 21572460, 87087001, 350739488, 1410132405, 5662052980, 22712782001, 91044838248, 364760483725, 1460785327100, 5848371485001, 23409176469808, 93683777468645, 374876324642820, 1499928942876001
Offset: 0

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Author

Keywords

Comments

Binomial transform of A085277. - Paul Barry, Jun 25 2003
Number of walks of length 2n+5 between two nodes at distance 5 in the cycle graph C_12. - Herbert Kociemba, Jul 05 2004

Crossrefs

Programs

  • GAP
    a:=[1,8,45];; for n in [4..30] do a[n]:=8*a[n-1]-19*a[n-2]+12*a[n-3]; od; Print(a); # Muniru A Asiru, Apr 19 2019
  • Mathematica
    Table[(2^(2*n + 3) - 3^(n + 2) + 1)/6, {n, 40}] (* Vladimir Joseph Stephan Orlovsky, Jan 19 2011 *)
    CoefficientList[Series[1/((1-x)(1-3x)(1-4x)),{x,0,30}],x] (* or *) LinearRecurrence[ {8,-19,12},{1,8,45},30] (* Harvey P. Dale, Apr 09 2012 *)
  • PARI
    Vec(1/((1-x)*(1-3*x)*(1-4*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 23 2012
    

Formula

a(n) = 16*4^n/3 + 1/6 - 9*3^n/2. - Paul Barry, Jun 25 2003
a(0) = 0, a(1) = 8, a(n) = 7*a(n-1) - 12*a(n-2) + 1. - Vincenzo Librandi, Feb 10 2011
a(0) = 1, a(1) = 8, a(2) = 45, a(n) = 8*a(n-1) - 19*a(n-2) + 12*a(n-3). - Harvey P. Dale, Apr 09 2012

A085278 Expansion of (1+2x)^2/((1-x^2)(1-2x)).

Original entry on oeis.org

1, 6, 17, 38, 81, 166, 337, 678, 1361, 2726, 5457, 10918, 21841, 43686, 87377, 174758, 349521, 699046, 1398097, 2796198, 5592401, 11184806, 22369617, 44739238, 89478481, 178956966, 357913937, 715827878, 1431655761, 2863311526
Offset: 0

Views

Author

Paul Barry, Jun 25 2003

Keywords

Comments

Binomial transform is A085277.

Programs

  • Mathematica
    CoefficientList[Series[(1+2x)^2/((1-x^2)(1-2x)),{x,0,40}],x] (* or *) LinearRecurrence[{2,1,-2},{1,6,17},40] (* Harvey P. Dale, Sep 19 2016 *)

Formula

a(n)=16*2^n/3+(-1)^n/6-9/2.
G.f.: (2*x+1)^2 / ( (x-1)*(2*x-1)*(1+x) ). - R. J. Mathar, Nov 20 2014

Extensions

Missing parenthesis in definition corrected by Harvey P. Dale, Sep 19 2016
Showing 1-2 of 2 results.