# Find a simple formula defining the nth term of the sequence

#### brumby_3

So stuck on this!

0, 1, 3, 8, 15...... that's the sequence.

I've got (n-1)^2 - 1 as a kind of answer, it's a bit off as it gives -1, 0, 3, 8, 15.

Any ideas?

#### brumby_3

Hey, thanks for the page but I can't understand it because there's too much going on.... where can I find the answer to my question?

#### Opalg

MHF Hall of Honor
That page lists all the sequences featuring 0, 1, 3, 8, 15 that occur in a very comprehensive list of sequences occurring in mathematics. None of them is given by a simple formula, and there does not seem to a natural formula that generates your sequence.

If I had to guess, I would say that the "1" should not be in the sequence that you were given, and that your suggested answer $$\displaystyle n^2-1$$ (where $$\displaystyle n\geqslant1$$) is the one that was expected.

brumby_3

#### brumby_3

Thanks for your answer. I did think of the n^2-1 previously, but obviously it's the closest it's gonna get. Thanks again!