A028814 Expansion of (1-2*x)/((1-x)^3*(1-4*x)).

1, 5, 20, 78, 307, 1219, 4862, 19428, 77685, 310705, 1242776, 4971050, 19884135, 79536463, 318145762, 1272582944, 5090331657, 20361326493, 81445305820, 325781223110, 1303124892251, 5212499568795, 20849998274950, 83399993099548, 333599972397917

Offset

0,2

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (7,-15,13,-4).

Formula

From Colin Barker, Apr 16 2016: (Start)

a(n) = (-10+4^(3+n)+15*n+9*n^2)/54.

a(n) = 6*a(n-1)-8*a(n-2)-2*a(n-3)+9*a(n-4)-4*a(n-5) for n>3.

(End)

Mathematica

LinearRecurrence[{7, -15, 13, -4}, {1, 5, 20, 78}, 25] (* Vaclav Kotesovec, Apr 16 2016 *)

Prog

(PARI) Vec((1-2*x)/((1-x)^3*(1-4*x)) + O(x^50)) \\ Colin Barker, Apr 16 2016

Crossrefs

Sequence in context: A129869 A271887 A079737 * A346394 A079820 A275907

Adjacent sequences: A028811 A028812 A028813 * A028815 A028816 A028817

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved