Methods for determining sequences.

I don't know if I'm in the right sub-forum here, but I've seen questions about sequences and series here before, so here we go.

Our teacher gave us a brainteaser by giving us the first nine numbers in a sequence and then challenging us to find the expression for $\displaystyle a_{n}$. The problem is that it's not very easy, and I'm not sure if I'm going to be able to solve it with my current set of skills. So my question is: Are there methods to find a possible sequence if given certain information, and if so, what are they and how advanced are they? What do I need to know in order to use them?

And btw, if you want to have a crack at the brainteaser I can post the first nine numbers, but I really wish to solve this one myself, so please don't post any spoilers in case that you solve it before I do.

Re: Methods for determining sequences.

Quote:

Originally Posted by

**scounged** I don't know if I'm in the right sub-forum here, but I've seen questions about sequences and series here before, so here we go.

Our teacher gave us a brainteaser by giving us the first nine numbers in a sequence and then challenging us to find the expression for $\displaystyle a_{n}$. The problem is that it's not very easy, and I'm not sure if I'm going to be able to solve it with my current set of skills. So my question is: Are there methods to find a possible sequence if given certain information, and if so, what are they and how advanced are they? What do I need to know in order to use them?

And btw, if you want to have a crack at the brainteaser I can post the first nine numbers, but I really wish to solve this one myself, so please don't post any spoilers in case that you solve it before I do.

Have a look at this website.

Re: Methods for determining sequences.

Yeah, I did check there, but the sequence wasn't in the database. I really hope that there is an actual sequence for the numbers and not our teacher just messing with us.

Re: Methods for determining sequences.

Quote:

Originally Posted by

**scounged** Yeah, I did check there, but the sequence wasn't in the database. I really hope that there is an actual sequence for the numbers and not our teacher just messing with us.

I bet he/she is messing with you ... most "sequences" people come up with are nothing more than playing "guess what was on my mind when I made this up".

Re: Methods for determining sequences.

Yeah, maybe. Then I guess there's no point in not showing the beginning of the "sequence". The first numbers are(in the order given):

1, 5, 4, 9, 6, 7, 3, 2, 8.

If you get it, just type in something like "Solved it!" so that I can know there is a reason not to give up.