Question

what is the next number in this series
2,5,17,65,257,...

Answer 1

Answer:

1025

Step-by-step explanation:

1) 2 = 1 ^ 2 + 1

2) 5 = 2 ^ 2 + 1

3) 17 = 4 ^ 2 + 1

4) 65 = 8 ^ 2 + 1

5) 257 = 16 ^ 2 + 1

6) 1025 = 32 ^ 2 + 1