@Carl Love

 Sorry for the late reply, I only have access to maple during the week.

This is my code

> h := 2*a;

> f :=  (h) -> h! -sum('3*f(2*m)*m', m = 1 .. (1/2)*h-1)

> f(2) := 3;

> g := (n) -> 3+2*n-(sum(sum(f(h), a = 1 .. floor((1/2)*m)), m = 1 .. n))

Everything works ok for the function f. I keep getting recursion errors for g though, I'm trying to evaluate g for non negative integers.

Thanks