program to calculate product of each column in matrix

Write a java program to print following pattern:-

        A
     ABA
   ABCAB
 ABCDABC

import java.util.Scanner;

public class CharPattern20 {

public static void main(String[] args) {

Scanner sc=new Scanner(System.in);

System.out.println("Enter Row size : ");

int n=sc.nextInt();

for(int i=0;i<n;i++) {

int k=1,l=2*i-1;

for(int j=0;j<n-i;j++) {

System.out.print(" ");

}

for(int j=0;j<l;j++) {

System.out.print((char)(64+k++)+"");

if(j==i-1)

k=1;

}

System.out.println();

}

}

}