Check if n is even then every set will contain 2 adjacent elements up - to n
if ( n % 2 == 0 ) { for ( int i = 0 ; i < n / 2 ; i ++ ) { firstadj = 2 * i + 1 ; secadj = 2 * i + 2 ; Console . Write ( " ( " + firstadj + " , ▁ " + secadj + " ) STRNEWLINE " ) ; } } else {