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

• May 13th 2010, 12:35 AM
brumby_3
Find a simple formula defining the nth term of the sequence
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?
• May 13th 2010, 01:25 AM
Opalg
• May 13th 2010, 01:32 AM
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?
• May 13th 2010, 01:48 AM
Opalg
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.
• May 13th 2010, 02:59 PM
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!