## University Calculus: Early Transcendentals (3rd Edition)

$a_n=0.5+(-1)^{n+1}(0.5)$
We can see that the terms are alternating between $0$ and $1$. $a_1=1$, so $a_n=0.5+(-1)^{n+1}(0.5)$ for all $n$ natural numbers.