Intermediate Mathematical Challenge 2012 Q17

The first term of a sequence of positive integers is 6. The other terms in the sequence follow these rules:

if a term is even then divide it by 2 to obtain the next term;if a term is odd then multiply it by 5 and subtract 1 to obtain the next term.

For which values of $n$ is the $n$th term equal to $n$? (e.g. if the 3rd term was 3, this would be a match)