Sum of all i such that ( 2 ^ i + 1 ) % 3 = 0 where i is in range [ 1 , n ] | Function to return the required sum ; Total odd numbers from 1 to n ; Sum of first n odd numbers ; Driver code
function sumN ( n ) { n = parseInt ( ( n + 1 ) / 2 ) ; return ( n * n ) ; } var n = 3 ; document . write ( sumN ( n ) ) ;