Odd numbers in N | Function to get no of set bits in binary representation of positive integer n ; Count number of 1 's in binary  representation of n. ; Number of odd numbers in n - th row is 2 raised to power the count . ; Driver code
function countSetBits ( n ) { let count = 0 ; while ( n > 0 ) { count += n & 1 ; n >>= 1 ; } return count ; } function countOfOddsPascal ( n ) { let c = countSetBits ( n ) ; return Math . pow ( 2 , c ) ; } let n = 20 ; document . write ( countOfOddsPascal ( n ) ) ;