Ok, so you need, if, for example, 5 is inputed, to show you 7, and if 7 is inputed to shouw you 11, and so on and so forth.
Well, we'll need a proof that you tried to solve your problem, so that we know where you're stuck. Post what you've done so far:).
public class GrossmontBank
//class variables (global - accessible throughout this class)
//scanner object to be used throughout
private static Scanner input = new Scanner(System.in);