  We show that there exists a fixed recursive function $e$ such that for all
functions $h\colon \mathbb{N}\to \mathbb{N}$, there exists an injective
function $c_h\colon \mathbb{N}\to \mathbb{N}$ such that $c_h(h(n))=e(c_h(n))$,
i.e., $h=c_h^{-1}ec_h$.
