Computes the value of a (statisticians') Hermite polynomial.
The value Hen(x).
Hermite polynomials are orthogonal on the interval (-∞,+∞) with a weight function equal to the standard normal probability distribution.

Their orthonormality relation makes them a useful basis for expressing pertubations arround a normal distribution.
Physicists' Hermite polynomials (see HermiteH(Int32, Double)) are related to statisticians' Hermite polynomials via Hn(x) = 2nHn(x √2).