F(n)=F(n-1)+F(n-2) for n>1
F(0)=F(1)=1
Recall that the generating function G(a_n) is defined as the function
of a real variable x, g(x), with a_n as the cofficients of the n-the
power of x in its power series expansion
g(x)=sum a_n·x^n for
n>-1 (this is an html joke)
Also, the simple fractional function 1/(1 -c·x) is the generating function of the sequence with general term c^n.