Question

1,3,10, 21,64, 129, ?,777 Ans-388 explan​

Answer 1

Step-by-step explanation:

1*2=2+1=3

3*3=9+1=10

10*2=20+1=21

21*3=63+1=64

64*2=128+1=129

129*3=387+1=388

388*2=776+1=777