[Guest]

Because my first attempt at a riddle was so miserable, here is a set of numbers.

2

3

5

7

??

21

23

27

What's the missing number? But more importantly, why?

There are 8 numbers.

[akaslickster]

12? Multiples

[Guest]

Sorry akaslickster, that's not it.

[Guest]

Because my first attempt at a riddle was so miserable, here is a set of numbers.

2

3

5

7

??

21

23

27

What's the missing number? But more importantly, why?

There are 8 numbers.

[Guest]

20, but the explaining I have is weird, so if it's right I will try and explain.

[Guest]

Sorry forix, but that's another swing and a miss.

Goodnight to all, I'll be back on later to check up on this.

[Guest]

Here is my attempt:

Since you say there are 8 numbers I think your using an octal base (Am I correct?). If you then translate this numbers to our regular decimal base you obtain the sequence:

2, 3, 5, 7, ??, 17, 19, 23.

Now all of the above are prime numbers.... however according to my logic there are two missing numbers in the sequence, namely 11 and 13. If you include this in the list and express them using an octal expression you get the sequence:

2, 3, 5, 7, 13, 15, 21, 23, 27.

Might not be the answer you are looking for but as I said before this is my attempt of explaining your puzzle.

[Guest]

Here is my attempt:

Since you say there are 8 numbers I think your using an octal base (Am I correct?). If you then translate this numbers to our regular decimal base you obtain the sequence:

2, 3, 5, 7, ??, 17, 19, 23.

Now all of the above are prime numbers.... however according to my logic there are two missing numbers in the sequence, namely 11 and 13. If you include this in the list and express them using an octal exp​ression you get the sequence:

2, 3, 5, 7, 13, 15, 21, 23, 27.

Might not be the answer you are looking for but as I said before this is my attempt of explaining your puzzle.

That's exactly it, and thank you for catching the fact that I missed 13. I definitely feel stupid, I blame it on my transcription of the prime numbers up to 200, in binary.

I'll be sure to edit the OP so in the future others can enjoy.

**Edit: I can't edit the OP anymore. Sorry to all those that would have been helped by the missing numbers.

Edited May 14, 2008 by MLeww

[akaslickster]

That's exactly it, and thank you for catching the fact that I missed 13. I definitely feel stupid, I blame it on my transcription of the prime numbers up to 200, in binary.

I'll be sure to edit the OP so in the future others can enjoy.

**Edit: I can't edit the OP anymore. Sorry to all those that would have been helped by the missing numbers.

You're forgiven MLeww, I'm kind of bad with math anyhow except for basic. I still may not had got it correct. Also, thanks for being there.

[Guest]

Cool

I knew my explanation wasn't that bad... it actually made a lot of sense to me but I was hesitant to post.

Anyway, thank you for the puzzle!