a) n -> n+2 -> n+4 -> n+6 -> n+8
b) n -> 2n -> 4n -> 8n -> 16n
c) n+2 -> n-3 -> n-8 -> n-13 -> n-18
d) 0n -> 2n -> 2n+2 -> 2n+4
e) 1n -> 2n+1 -> 2n+3 -> 2n+5
