A121986 Expansion of x*(-1+2*x-3*x^3+x^4)/((x^3+x^2+x-1) * (x-1)^2).

1, 1, 1, 4, 8, 16, 32, 61, 115, 215, 399, 738, 1362, 2510, 4622, 8507, 15653, 28797, 52973, 97440, 179228, 329660, 606348, 1115257, 2051287, 3772915, 6939483, 12763710, 23476134, 43179354, 79419226

Offset

1,4

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (3, -2, 0, -1, 1).

Formula

a(n) = 3*a(n-1) -2*a(n-2) -a(n-4) +a(n-5).

Mathematica

Rest[CoefficientList[Series[x*(-1 + 2*x - 3*x^3 + x^4)/((x^3 + x^2 + x - 1)*(x - 1)^2), {x, 0, 50}], x]] (* or *) LinearRecurrence[{3, -2, 0, -1, 1}, {1, 1, 1, 4, 8}, 50] (* G. C. Greubel, Sep 14 2017 *)

Prog

(PARI) x='x+O('x^50); Vec(x*(-1+2*x-3*x^3+x^4)/((x^3+x^2+x-1)*(x-1)^2)) \\ G. C. Greubel, Sep 14 2017

Crossrefs

Cf. A014125.

Sequence in context: A007096 A298356 A036313 * A285906 A172042 A352918

Adjacent sequences: A121983 A121984 A121985 * A121987 A121988 A121989

Keyword

nonn,easy

Author

Roger L. Bagula, Sep 09 2006

Extensions

Definition replaced with generating function by the Assoc. Eds. of the OEIS, Mar 27 2010

Status

approved