pub fn laguerre(n: u32, x: f64) -> f64
Laguerre polynomial L_n(x). L_0 = 1, L_1 = 1 − x, (n+1)L_{n+1} = (2n+1−x)L_n − n L_{n-1}.
L_n(x)
L_0 = 1
L_1 = 1 − x
(n+1)L_{n+1} = (2n+1−x)L_n − n L_{n-1}