A153388 Second bisection of A153382.

8, 18, 48, 128, 338, 888, 2328, 6098, 15968, 41808, 109458, 286568, 750248, 1964178, 5142288, 13462688, 35245778, 92274648, 241578168, 632459858, 1655801408, 4334944368, 11349031698, 29712150728, 77787420488, 203650110738, 533162911728, 1395838624448

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (4,-4,1).

Formula

a(n)= 4*a(n-1)-4*a(n-2)+a(n-3) = 10*A001519(n+1)-2. G.f.: 2*(4-7x+4x^2)/((1-x)(1-3x+x^2)). - R. J. Mathar, Jan 23 2009

a(n) = 2^(-n)*(-2^(1+n)-(3-sqrt(5))^n*(-5+sqrt(5))+(3+sqrt(5))^n*(5+sqrt(5))). - Colin Barker, Nov 03 2016

Mathematica

LinearRecurrence[{4, -4, 1}, {8, 18, 48}, 30] (* Harvey P. Dale, Nov 04 2015 *)

Prog

(PARI) Vec(2*(4-7*x+4*x^2)/((1-x)*(1-3*x+x^2)) + O(x^30)) \\ Colin Barker, Nov 03 2016

Crossrefs

Sequence in context: A192311 A300161 A034714 * A109988 A335440 A066721

Adjacent sequences: A153385 A153386 A153387 * A153389 A153390 A153391

Keyword

nonn,easy

Author

Paul Curtz, Dec 25 2008

Extensions

More terms from R. J. Mathar, Jan 23 2009

Status

approved