Darklands Puzzle #25

A door blocks the path. On it are carved the following words:
PRESS THE NEXT NUMBER.
1 2 3 5 7 11 13 17 19 23
Upon the door are five numbered knobs. Clearly, you are supposed to press one of the knobs. But what is next in the sequence? The wrong choice may (will. ed.) release a horrible trap! You cogitate, then press...
...knob 25.
...knob 26.
...knob 27.
...knob 29.
...knob 31.

(Source: Darklands cluebook by MicroProse Software)

Almost all of these are prime numbers! The writers at MicroProse Software must have forgotten that the primes start at two. The next prime number after 23 is 29 so press knob 29.