Shell Script to print first n natural numbers in a pattern of Right angled Triangle

Program

#! /bin/bash
read -p "Enter a n: " n
	for((i=1;i<=n;i++))
	do
		for((j=i;j<=n;j++))
		do
			echo -ne " "
		done
		for((k=1;k<=i;k++))
		do
			echo -ne "$k"
		done
		for((l==(i-1);l>=1;l++))
		do
			echo -ne "$l"
		done
	echo
done

Output

$ chmod 755 number_pattern_1.sh
$ sh number_pattern_1.sh
Enter a n: 5
    1
   12
  123
 1234
12345