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.

A077919 Expansion of (1-x)^(-1)/(1+2*x-2*x^2+2*x^3).

Original entry on oeis.org

1, -1, 5, -13, 39, -113, 331, -965, 2819, -8229, 24027, -70149, 204811, -597973, 1745867, -5097301, 14882283, -43450901, 126860971, -370388309, 1081400363, -3157299285, 9218175915, -26913751125, 78578452651, -229420759381, 669825926315, -1955650276693, 5709793924779
Offset: 0

Views

Author

N. J. A. Sloane, Nov 17 2002

Keywords

Programs

  • Mathematica
    CoefficientList[Series[(1-x)^(-1)/(1+2x-2x^2+2x^3),{x,0,40}],x] (* or *) LinearRecurrence[{-1,4,-4,2},{1,-1,5,-13},40] (* Harvey P. Dale, Aug 22 2013 *)

Formula

a(0)=1, a(1)=-1, a(2)=5, a(3)=-13, a(n)=a(n-1)+4*a(n-2)-4*a(n-3)+2*a(n-4). - Harvey P. Dale, Aug 22 2013