Maxima can't seem to evaluate numerically float(exp(exp(2))) .
(C30) float(exp(exp(2)));
2
%E
(D30) 2.718281828459045
I used the following workaround:
y(x) := EXP(FLOAT(EXP(x))) ROMBERG(EXP(- EXP(s)), s, 1, x)
Ugly!