How to create a script in Linux that makes a pyramid of asterisks with the pattern 1, 3, 5, 7, 9, 11, 13, 15, 17 centered -

i'm trying write shell script print pyramid of asterisks this:

        *        ***       *****      *******     *********    ***********   *************  *************** ***************** 

below attempt far. when run it, errors arithmetic expression required. doing wrong?

for (( = 1; <= n, i++ ));     (( k = i; k <= n, k++ ));         echo -ne " "     done      (( j = 1; j <= 2 * - 1, j++ ));         echo -ne "*"     done      echo done 

the syntax of arithmetic for-loop uses 2 semicolons, not semicolon , comma:

for (( = 1; <= n; i++ )); 

(the individual components may contain commas — example, i++, j++ expression increments both i , j — has no specific relevance for.)