OFFSET
0,2
COMMENTS
a(8) is approximately 5.698 * 10^93.
The denominator of z(n) is 2^(2^n) for n > 0.
Given that the iteration of z(n) escapes to infinity, this shows that 1 is not in the Julia set for the function z^2 + 1/4. This is of course also true of -1.
EXAMPLE
1^2 + 1/4 = 5/4, hence a(1) = 5.
(5/4)^2 + 1/4 = 25/16 + 4/16 = 29/16, hence a(2) = 29.
MATHEMATICA
Numerator[NestList[#^2 + 1/4 &, 1, 8]]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Alonso del Arte, Jun 04 2016
STATUS
approved