Consider the following infinite set A

$=$

$\{$

$1$

$,$

$5$

$,$

$1$

$3$

$,$

$2$

$9$

$,$

$6$

$1$

$\}$

$$ a

$.$

$($

Describe the pattern to obtain a element from the previous element. b

$)$

$$give recursive definition of the Set A

$.$