Automaticity of the sequence of the last nonzero digits of n ! in a fixed base
Eryk Tadeusz Lipka · Journal de Théorie des Nombres de Bordeaux · 2019
In 2011 Deshouillers and Ruzsa [5] tried to argue that the sequence of the last nonzero digit of n ! in base 12 is not automatic. This statement was proven a few years later by Deshoulliers in [4]. In this paper we provide an alternate proof that lets us generalize the problem and give an exact characterization of the bases for which the sequence of the last nonzero digits of n ! is automatic.