## Normal to recursive method due tomorrow please help!!

I need to make run() a recursive method, and i have no way of doing it. I tried many ways but cannot do it. Can someone please help me, it's due tomorrow and I've spent hours on it.

Program:
Write a program that prompts for a positive integer and displays all permutations of the odd digits of that length. Display these values in ascending order. For example, if the length is 3, your program should display:

111
113
115
117
119
131
133
135
. . .

^there shouldn't be an even digit in any number.

Java Code:
```   import java.util.Scanner;
public class OddDigits
{
public static void main(String [] arg)
{
Scanner x = new Scanner(System.in);

System.out.print("Enter a number: ");
int a = x.nextInt();
int b = 1;

run(a, b);
}

public static boolean isOdd(int a)
{
int n =0;
while (a > 1)
{
if(a%2 == 0)
return false;
a = a/10;
}

return true;
}

public static void run(int a, int b)
{
int upLim = (int)Math.pow(10,a);
int lowLim = (int)Math.pow(10, a-1) -1;

int start = (int)Math.pow(10, a-1);

while(start < upLim)
{
if(isOdd(start) == true)
System.out.println(start);
start++;
}
//run(a, start++);
}

}```