Note: Alternately, we add `4` and double the next. So, `132` is wrong.

Note: Not available

Note: Each number is the preceding number multiplied by `- 2. So, the missing number is `- 128`

Note: Number are alternately multiplied by `2` and increased by `3` So, the missing number `61 xx 2 = 122`

Note: Numbers are `1^2, 2^2, 3^2, 4^2, 5^2, 6^2, 7^2` So, the next number is `8^2 = 64`

Note: Numbers are `1^3, 2^3, 3^3, 4^3, 5^3, 6^3.` So, the missing number is `7^3 = 343`.

Note: Numbers are all primes. The next prime is `43`

Note: Each number is twice the preceding one with `1` added or subtracted alternately. So the next number is `(2 xx 261 + 1) = 523`

Note: There are two series, beginning respectively with `3` and `7`. In one `3` is added and in another `2` is subtracted. The next number is `1 - 2 = -1`

Note: Each number is double the preceding one plus `1` So, the next number is `(255 xx 2) + 1 = 511`