Possible Duplicate:
When do the multiples of two primes span all large enough natural numbers?
We have to generate a number by using only 3's and 5's.
For ex :
3 = 3
4 can't be generated
5 = 5
6 = 3 + 3
7 can't be generated
8 = 3 + 5
9 = 3 + 3 + 3
10 = 5 + 5
11 = 3 + 3 + 5
and so on...
So from 8, every integer i.e. 9,10,11,12,.. can be generated by using 3's and 5's.
But I can't prove it. So
(i) Is there a way to prove that every integer after 7, can be generated
by using only 3's and 5's ?
(ii)Are there any other pairs of numbers (as 3 and 5 here), which satisfy
this property that after certain integer, all integers can be generated
by using number only from that pair ?
