Question 989672
Each previous term is being multiplied by 3 to get the next term


1*3 = 3
3*3 = 9
9*3 = 27
27*3 = 81
etc etc


The next three numbers would be


81*3 = <font color="red">243</font>
243*3 = <font color="red">729</font>
729*3 = <font color="red">2187</font>