Exponential generating functions for the associated Bessel functions

Abstract: Similar to the associated Legendre functions, the differential equation for the associated Bessel functions $B_{l,m}(x)$ is introduced so that its form remains invariant under the transformation $l\rightarrow -l-1$. A Rodrigues formula for the associated Bessel functions as squared integrable solutions in both regions $l<0$ and $l\geq 0$ is presented. The functions with the same $m$ but with different positive and negative values of $l$ are not independent of each other, while the functions with the same $l+m$ ($l-m$) but with different values of $l$ and $m$ are independent of each other. So, all the functions $B_{l,m}(x)$ may be taken into account as the union of the increasing (decreasing) infinite sequences with respect to $l$. It is shown that two new different types of exponential generating functions are attributed to the associated Bessel functions corresponding to these rearranged sequences.