@Ronan 

Thank you very much for your response, I'm wondering if there's a method to obtain the values of this sum without using the "proc" command. I'm interested in exploring an alternative approach if possible.

Thank you again for your help!

@Thomas Richard 

yes that's exactly what i'm looking for

Thank you very much.

@tomleslie 

thanks for your reply, but i want the values of bi to be in order of powers of x for example

for n=1: (3,2,3)

n=2: (9, 12,22,12,9)

@Rouben Rostamian  

thank you very much it works very well