Question

Question 1 of 20
1,3,9,31,?,651

Answer 1

Answer:

nth term =( (n-1)th term * (n-1)) + (n)

1st term = 1,

2nd term = (1*1) + 2=3;

3rd term = (3*2)+3=9;

4th term= (9*3)+4=31;

5th term=(31*4)+5=129;

6th term=(129*5)+6=651

Thus 651 is the answer. :-)