I am so sorry for misleading you. I needed to solve this problem, because it occurred to me whilst I was solving another one. Indeed, what I had written is not true. In such case, could you help me find all integers for which
i divisible by
?
Last edited by gollum; September 21st 2011 at 10:55 AM.
You could try to show that the ratio increases towards a limiting value 4. The ratio is equal to 3 when n=1. For n>1, it will lie between 3 and 4, so can never again be an integer.