I've seen this task once in one IQ test: "Continue the row of numbers - 2, 4, 8, 16, 19, ..."
The answer was - 21... "You know, first we multiply by 2 and then we start to add 3" :) . Perfect "creative thinking" test.
The IQ tests, even if they are valid are still inherently broken, just forget about them and carry on.