What is the $21$21st term in the following sequence?
$-3,-6,-9,-12,-15,\ldots$−3,−6,−9,−12,−15,…
What is the $53$53rd term in the following sequence?
What is the $39$39th term in the following sequence?
If $T_n$Tn describes the $n$nth term in the following sequence, what is $T_3+T_5$T3+T5?