9. Sequences, Series, & Induction

In Exercises 19–22, the general term of a sequence is given and involves a factorial. Write the first four terms of each sequence. a_n = n²/n!

In Exercises 61–68, use the graphs of and to find each indicated sum.

${\sum }_{i=1}^5{a}_i^2+{\sum }_{i=1}^5{b}_i^2$

Evaluate each factorial expression. 16!/2!14!