Series of number consists only 3 & 4

i/p:
9
o/p:
3 4 33 34 43 44 333 334 343


import java.util.*;
public class NewClass21 {
    void print(int ar[],int n)
    {
        for(int i=0;i<n;i++)
           System.out.print(ar[i]+" ");
    }
    void series(int ar[],int n)
    {
        ar[0]=3; ar[1]=4;
        int k=1,i;
        for(i=0;k<n;i++)       //or k<n-2
        {
            ar[++k]=(ar[i]*10)+3;
           ar[++k]=(ar[i]*10)+4; 
        }
          //or   if(n%2==1)
            //   ar[++k]=ar[i]*10+3;
    }
    public static void main(String args[])
    {
        Scanner s=new Scanner(System.in);
      
        int n=s.nextInt();
        int ar[]=new int[n+2];  //or n
        NewClass21 ob=new NewClass21();
        ob.series( ar,n);
        ob.print(ar,n);
    }
}