What is the maximum number which is smaller than n, such that sum of number of divisors of divisors of this number is maximum?
For example,
g(n) = number of divisors of n
f(12) = g(1) + g(2) + g(3) + g(4) + g(6) + g(12)
f(12) = (1) + (2) + (2) + (3) + (4) + (6) = 18
Can you help about it?