list( x = c( 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20) , 
y = c( 4.886847, 7.565152, 9.489578, 11.329, 12.20413, 15.7251, 15.62605, 
19.11223, 19.93379, 25.3131, 26.87668, 29.17834, 30.04112, 30.57876, 31.63271, 
36.25937, 37.98598, 40.23416) , n = 18 , x1 = 30 )