next in sequence

Originally posted by TheNinjunny
Of course what is being assumed here is that this number sequence is derived mathmaticaly (by which I mean following a function).... to which I give you another sequence.
1
3
5
7
11
13
17
??

how about this sequence of very special numbers

561
1105
1729
2465
2821
6601
??

or this one
3 7 31 127 8191 131071 ??

Originally posted by TheNinjunny
Of course what is being assumed here is that this number sequence is derived mathmaticaly (by which I mean following a function).... to which I give you another sequence.
1
3
5
7
11
13
17
??

The interesting part of a solution of this kind of problem isn't the next number itself but how the next number is formed.

How can the next number of
1 3 5 7 11 13 17
be 19?

It could evidently not be every odd number starting from 1, where is 9 and 15?
So if the solution is 19, remembering that 1 is not a prime but 2 is, how is the serie formed?

how about odd non-composites

Originally posted by aginis
did you mean 2,3,5,7,11,13,17 ?

Originally posted by TheNinjunny
😳, woops ya I did mean 2 not 1, oh well I think my point remains valid.