OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-4,-1,2).
FORMULA
Fibonacci(n+2) + 2^(n+1) + 2. - Ralf Stephan, May 16 2007
a(n)= 4*a(n-1) -4*a(n-2) -a(n-3) +2*a(n-4). G.f.: (1-3*x^2)/((1-x) * (2*x-1) * (x^2+x-1)). - R. J. Mathar, Feb 06 2010
a(n) = (-2+2^(1+n)+(2^(-1-n)*((1-sqrt(5))^n*(-3+sqrt(5))+(1+sqrt(5))^n*(3+sqrt(5))))/sqrt(5)). - Colin Barker, Nov 03 2016
MAPLE
seq(sum(2^x+fibonacci(x), x=0..a), a=0..30);
PROG
(PARI) Vec((1-3*x^2)/((1-x)*(2*x-1)*(x^2+x-1)) + O(x^40)) \\ Colin Barker, Nov 03 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jorge Coveiro, Dec 25 2004
STATUS
approved