Use Trace to Evaluate a Sequence Equation
You are going to love using the Trace feature on the TI84 Plus to evaluate sequences. Remember, you are not tracing xvalues as you do in Function mode. Follow these steps to evaluate a sequence at specific n values:

Press [TRACE].
See the first screen. Your trace starts at the smallest n value on the graph. The values of X and Y are displayed in the border at the bottom of your graph screen.
The TI84 Plus C displays functions and information in the border of the graph screen. The TI84 Plus displays similar information directly on the graph screen.

Press the rightarrow key to find the next term in the sequence.
Notice, your cursor jumps from one point to the next.

Enter a specific n value.
After pressing [TRACE], entering a number opens up an entry line in the border at the bottom of your graph screen.

Press [ENTER].
While using Trace, you can enter a specific n value that is larger than the Xmax. As long as you enter a value smaller than nMax, you won’t get an error message! See the second screen.
You don’t need a graph to evaluate a sequence. Instead, use your calculator by pressing [2nd][MODE]. Enter u by pressing [ALPHA][TRACE][ENTER], then press [(] and the nvalue you would like to evaluate. See the third screen.