Count of Octal numbers upto N digits | Java program to find the count of natural octal numbers upto N digits ; Function to return the count of natural octal numbers upto N digits ; Loop to iterate from 1 to N and calculating number of octal numbers for every ' i ' th digit . ; Driver code
public class GFG { static int count ( int N ) { int sum = 0 ; for ( int i = 1 ; i <= N ; i ++ ) { sum += 7 * Math . pow ( 8 , i - 1 ) ; } return sum ; } public static void main ( String [ ] args ) { int N = 4 ; System . out . println ( count ( N ) ) ; } }