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

Author

Paul Curtz, Dec 25 2008

Keywords

• nonn
• easy

Links

• Colin Barker, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (4,-4,1).

Programs

Mathematica

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

PARI

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

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

Extensions

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