A collection of 2015 balls are numbered from 1 to 2015. Each ball may be coloured green or red according to the following rules:
(i) If balls \(a\) and \(b\) are two different red balls with \(a+b \leq 2015\), the ball \(a+b\) is also red.
(ii) If ball \(a\) is red and another ball \(b\) is green with \(a+b \leq 2015\), then \(a+b\) is green.
Find, with proof, the number of different possible ways of colouring the 2015 balls.
Bonus: Generalise this for \(n\) balls.