Count of 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
function count ( N ) { var sum = 0 ; for ( var i = 1 ; i <= N ; i ++ ) { sum += 7 * Math . pow ( 8 , i - 1 ) ; } return sum ; } var N = 4 ; document . write ( count ( N ) ) ;