Find \[\sum_{n = 1}^\infty \frac{n^2 + n - 1}{(n + 2)!}.\]
listfor(n, 1, 10000, (n^2+n-1) / (n+2)! ==(1 / 6, 5 / 24, 11 / 120, 19 / 720, 29 / 5040, 41 / 40320, 11 / 72576, 71 / 3628800, 89 / 39916800, 109 / 479001600........etc==It converges to 1 / 2