Special sequences

There are some special sequences that you should recognise that are not linear or quadratic.

The most important of these are:

cube numbers: 1, 8, 27, 64, 125, ...
triangular numbers: 1, 3, 6, 10, 15, ... (these numbers are quadratic, and the \(n\)th term is \(\frac{1}{2}n^2 + \frac{1}{2}n\))
Fibonacci sequence: 1, 1, 2, 3, 5, 8, 13, ... (in this sequence you start off with 1, and then to get each term you add the two terms that come before it)

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