Up to n=200, A007408(n) behaves roughly like 10^(1.3 n) and there are only 14 points (for n < 200) such that A007408(n) >= A007408(n+1); they are all such that A007408(n)>A007408(n+1) < A007408(n+2).
EXAMPLE
a(1) = 5 since k=5 is the smallest index such that A007408(k)>=A007408(k+1).
