text: Traverse through the all possible elements
code: for ( i = 1 ; i <= maxi ; i ++ ) { if ( mobius [ i ] == 0 ) continue ; var temp = 0 ; for ( j = i ; j <= maxi ; j += i ) temp = parseInt ( temp + fre [ j ] ) ; ans += parseInt ( temp * ( temp - 1 ) / 2 * mobius [ i ] ) ; }