I want to plot ( Cp, ) in matlab ( like the graph below) . what is step?

where

The coefficients c1 to c6 are: c1 = 0.5176, c2 = 116, c3 = 0.4, c4 = 5, c5 = 21 and c6 = 0.0068

= 0^o 1^o , 2^o.............15