We prove that the ordinary generating function of Bell numbers satisfies
no algebraic differential equation over C(x) (in fact,
over a larger field). We investigate related numbers counting various set
partitions (the Uppuluri-Carpenter numbers, the numbers of partitions with
j mod i blocks, the Bessel numbers, the numbers of
connected partitions, and the numbers of crossing partitions) and prove
for their ogf's analogous results. Recurrences, functional equations, and
continued fraction expansions are derived.