Closed formula for physicist's Hermite polynomials
From specialfunctionswiki
Theorem
The following formula holds: $$H_n(x)=\displaystyle\sum_{k=0}^{\lfloor \frac{n}{2} \rfloor} \dfrac{(-1)^k n! (2k)^{n-2k}}{k! (n-2k)!},$$ where $H_n$ denotes the physicist's Hermite polynomials and $k!$ denotes the factorial.
Proof
References
- 1960: Earl David Rainville: Special Functions ... (previous) ... (next): $103. (2)$