👉 A prehalter is a type of mathematical function that can be expressed in terms of the hypergeometric function. It is defined as follows: $$ \frac{1}{2} (\alpha + 1) \cdot \sum_{k=0}^{\infty} \binom{n-1+k}{n-k-1} (-x)^k $$ where $\alpha$ is a positive real number, and the sum ranges over all integers $k$ from 0