Which formula can be used to describe the sequence below?
[tex]
27,9,3,1, \frac{1}{3} \text {, }
[/tex]
[tex]a_n=-3 a_{n-1}, a_1=27[/tex]
[tex]a_n=\frac{1}{3} a_{n-1} ; a_1=27[/tex]
[tex]a_n=a_{n-1}-3 ; a_1=27[/tex]
[tex]a_n=3 a_{n-1}-\frac{1}{3} ; a_1=27[/tex]