Well, you could go with the triangular number sequence:
x=n(n+1)/2
Which ends up to look like: 1, 3, 6, 10, 15, 21, 28, 36, 45 ... etc.
OR.
Another sequence that would be good for hop additions would probably be Square numbers.
x^2
Which looks like: 1, 4, 9, 16, 25, 36, 49, 64.... and...