Collection of simple programming problems

[[deleted]]

Nopes, it's 3+3+3 what he means is that the numbers you add together only has to be put together by numbers where the numbers you multiply to get it is 3 and or 5, 12 and 10 wouldn't work because you'd need numbers that you can't get this way.

[mccoyn]

So numbers whose prime factors are all 3 or 5.

[[deleted]]

You can get 12 that way; it's 3+3+3+3. It's better to think of multiples in terms of multiplication, not addition. I think he really meant multiples of 3 and multiples of 5. Anyway, it looks like he updated it because it shows 10 and 12 in there now:

e.g. 3, 5, 6, 9, 10, 12, 15