It follows the logic below: 15 x 2 = 30 + 1 = 31 31 x 2 = 62 + 1 = 63 63 x 2 = 126 + 1 = 127 127x 2 = 254 + 1 = 255 255x 2 = 510 + 1 = 511
The answer is 511
The series contains ((2^n)-1) terms starting with n=4. So the required term will have n=9 => 512 -1 = 511.
511 will complete the series as indicated below:
The pattern shows that the numbers are doubled with a "1" added in. Starting with 15x2 = 30 + 1 = 31. And ending with 255x2 = 510 +1 = 511.
each consecutive number is add up with 16,32,64,128,.....
31-15=16 63-31 =32
127-63 =64
255-127=128
.....-255=256 so value is (256+255=511)
