Integral Test...Calculus 2?

Use the integral test to determine the convergence or divergence of the series.

1/2 + 1/5 + 1/10 + 1/17 + 1/26 + . . .

I just need the function that can be made from the given list of numbers. I can take it from there.

$a_n=\dfrac 1 {n^2+1}, ~~n\in \mathbb{N}$