Problem 350
Constraining the least greatest and the greatest least

A list of size n is a sequence of n natural numbers.
Examples are (2,4,6), (2,6,4), (10,6,15,6), and (11).

The greatest common divisor, or gcd, of a list is the largest natural number that divides all entries of the list.
Examples: gcd(2,6,4) = 2, gcd(10,6,15,6) = 1 and gcd(11) = 11.

The least common multiple, or lcm, of a list is the smallest natural number divisible by each entry of the list.
Examples: lcm(2,6,4) = 12, lcm(10,6,15,6) = 30 and lcm(11) = 11.

Let f(G, L, N) be the number of lists of size N with gcd ≥G and lcm ≤L. For example:

f(10, 100, 1) = 91.
f(10, 100, 2) = 327.
f(10, 100, 3) = 1135.
f(10, 100, 1000) mod 1014 = 3286053.

Find f(106, 1012, 1018) mod 1014.

These problems are part of Project Euler and are licensed under CC BY-NC-SA 2.0 UK

http://projecteuler.net/problem=350