5.1 Generating by Formula
Example 5.1a
Suppose we have a formula Un = 3n – 1. We can find any term of the sequence by replacing n by the number of the required term.
So we can get the first three terms thus:
| Note that only the n changes value as required, all the other bits of the formula stay as they are. |
But the beauty of this is that, suppose we want to find, say, the 15th term. We don’t have to find each and every term preceding the 15th. We can home in on it:
