Problem 326Published on Saturday, 26th February 2011, 04:00 pm; Solved by 322
Let an be a sequence recursively defined by: .
So the first 10 elements of an are: 1,1,0,3,0,3,5,4,1,9.
Let f(N,M) represent the number of pairs (p,q) such that:
It can be seen that f(10,10)=4 with the pairs (3,3), (5,5), (7,9) and (9,10).
You are also given that f(104,103)=97158.