Given the values of integers 1 a1
a2
...
an, consider the linear combination
q1a1 + q2a2 + ... + qnan = b, using only integer values qk 0.
Note that for a given set of ak, it may be that not all values of b are possible.
For instance, if a1 = 5 and a2 = 7, there are no q1 0 and q2
0 such that b could be
1, 2, 3, 4, 6, 8, 9, 11, 13, 16, 18 or 23.
In fact, 23 is the largest impossible value of b for a1 = 5 and a2 = 7.
We therefore call f(5, 7) = 23.
Similarly, it can be shown that f(6, 10, 15)=29 and f(14, 22, 77) = 195.
Find f(p*q,p*r,q*r), where p, q and r are prime numbers and p < q
r
5000.
These problems are part of Project Euler and are licensed under CC BY-NC-SA 2.0 UK