Analytic "Lagrange" interpolation for a countably infinite set of points?
There is this theorem:
Given two sequences $z_n$ and $w_n$ of complex numbers such that $|z_n| \to \infty$, there exists a holomorphic function $f$ such that $f(z_n) = w_n$ for all $n$.
It is a consequence of the Weierstrass factorization theorem and the Mittag-Leffler theorem.
See this question.