5-Smooth Pairs (noch nicht übersetzt)
Problem 682
5-smooth numbers are numbers whose largest prime factor doesn't exceed 5.
5-smooth numbers are also called Hamming numbers.
Let Ω(a) be the count of prime factors of a (counted with multiplicity).
Let s(a) be the sum of the prime factors of a (with multiplicity).
For example, Ω(300)=5 and s(300)=2+2+3+5+5=17.
Let f(n) be the number of pairs, (p,q), of Hamming numbers such that Ω(p)=Ω(q) and s(p)+s(q)=n.
You are given f(10)=4 (the pairs are (4,9),(5,5),(6,6),(9,4)) and f(102)=3629.
Find f(107)mod1000000007.