6, 13, 18, 25, 30, 37, 40

The terms are successively divided by 12, 10, 8, 6, ...etc.

So, 24 is wrong, it should be 8 (48/6 = 8).

Prime numbers 2, 3, 5, 7, 11, 13 are to be added successively.

So, 165 is wrong.

Terms at odd places are 5, 6, 7, 8 etc. and each term at even place is 16.

So, 9 is wrong.

Subtract 20, 25, 30, 35, 40, 45 from successive numbers.

So, 0 is wrong.

Each number is a composite number except 11.

The terms are alternatively multiplied by 1.5 and divided by 3. However, 18.5 does not satisfy it.

The numbers are 7 x 8, 8 x 9, 9 x 10, 10 x 11, 11 x 12, 12 x 13.

So, 150 is wrong.

The numbers are squares of odd natural numbers, starting from 5 up to 15.

So, 36 is wrong.

Each number is twice the preceding one with 1 added or subtracted alternatively.

So, the next number is (2 x 261 + 1) = 523.

There are two series (10, 13, 16, 19) and (5, 10, 20, 40), one increasing by 3 and the other multiplied by 2.