1, 3, 10, 21, 64, 129, 356, 777

Go on adding 7, 9, 11, 13, 15, 17 respectively to obtain the next number.

So, 33 is wrong. It must be 35

Go on subtracting 24, 21, 18, 15, 12, 9 from the numbers to get the next number.

190 - 24 = 166
166 - 21 = 145
145 - 18 = 127 [Here, 128 is placed instead of 127]
127 - 15 = 112
112 - 12 = 100 ... and so on.

Therefore, 128 is wrong.

Go on subtracting 3 and dividing the result by 2 to obtain the next number.

Clearly, 46 is wrong.

Numbers must be (14)², (13)², (12)², (11)², (10)², (9)², (8)².

So, 80 is wrong.

Go on multiplying with 1, 2, 3, 4, 5, 6 to get next number.

So, 96 is wrong.

Each even term of the series is obtained by multiplying the previous term by 2.

2^nd term = (1^st term) x 2 = 6 x 2 = 12

4^th term = (3^rd term) x 2 = 48 x 2 = 96.

6^th term = (5^th term) x 2 = 384 x 2 =768.

∴ 4^th term should be 96 instead of 100.

Go on dividing by 4 to get the next number.

So, 200 is wrong.

Go on multiplying 2 and adding 1 to get the next number.

So, 39 is wrong.

Go on adding 7, 9, 11, 13, 15, 17, 19 respectively to obtain the next number.

So, 135 is wrong.

2^nd term = (1^st term) x 1 + 1 = 15 x 1 + 1 = 16.

3^rd term = (2^nd term) x 2 + 2 = 16 x 2 + 2 = 34.

4^th term = (3^th term) x 3 + 3 = 34 x 3 + 3 = 105.

5^th term = (4^th term) x 4 + 4 = 105 x 4 + 4 = 424

6^th term = (5^th term) x 5 + 5 = 424 x 5 + 5 = 2125

∴ 6^th term should 2125 instead of 2124.