OFFSET
0,1
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,0,-1).
FORMULA
a(n) = Fibonacci(n+5) - 1.
a(n) = 2*a(n-1) - a(n-3).
From Colin Barker, Mar 22 2016: (Start)
a(n) = (-1+(2^(-1-n)*((1-sqrt(5))^n*(-11+5*sqrt(5))+(1+sqrt(5))^n*(11+5*sqrt(5))))/sqrt(5)).
G.f.: (4-x-2*x^2) / ((1-x)*(1-x-x^2)).
(End)
MATHEMATICA
Join[{a=4, b=7}, Table[c=a+b+1; a=b; b=c, {n, 0, 60}]] (* Vladimir Joseph Stephan Orlovsky, Nov 22 2010 *)
PROG
(PARI) Vec((4-x-2*x^2)/((1-x)*(1-x-x^2)) + O(x^50)) \\ Colin Barker, Mar 22 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved