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
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Dec 25 2008
EXTENSIONS
More terms from R. J. Mathar, Jan 23 2009
STATUS
approved