OFFSET
0,1
COMMENTS
If f(k) = f(k-1)*c^(1/k) - 1 for k > 1 and c > e = 2.718281828..., then as long as f(1) is large enough, f(k) can always be positive.
EXAMPLE
For n=0, f(1) = 0 and f(2) = -1 < 0. Thus, a(0) = 2.
PROG
(PARI) a(n) = {my(k=1, f=n); while(f>0, f=f*sqrtn(2, k++)-1); k+!n; }
CROSSREFS
KEYWORD
nonn
AUTHOR
Jinyuan Wang, Mar 31 2020
STATUS
approved