Consider the series

$$n$=$n$0\backslash$infty an$=($x$6)3+($x$6)622!+($x$6)943!+($x$6)1284!+$

Find an expression for an

$.$

an$=$

In the summation formula n

starts at n$=$n$0$

$.$ What is your starting index n$0$

$?$

n$0=$

$($Note that because the validity of either of your answers depends on the other, if you enter only one, both will be marked wrong.$)$