What is the next number 3 9 21 39 63?

NB

3,9,21,39,63.

We note that

#1;The difference between 3 & 9 = 6

#2 ;The difference between 9 & 21 = 12 ( 2 x 6)

#3 ; The difference between 21 & 39 = 18 ( 3 x 6)

#4 ; The difference between 39 & 63 = 24 ( 4 x 6)

So it follows

#5 ; The difference between 63 & X = ( 5 x 6 = 30 )

So 63 + 30 = 93 The answer !!!!!