Prove that the number of partitions of the positive integer n into parts each of which is at most 2 equals ⌊ n/2 ⌋ + 1. (Remark: There is a formula, namely the nearest integer to (n+3)^2/12, for the number of partitions of n into parts each of which is at most 3 but it is much more difficult to prove. There is also one for partitions with no part more than 4, but it is even more complicated and difficult to prove.)