A Function in the Number Theory
  In this paper one constructs a function $\eta$ with the property that if $n$ is non-null then $\eta(n)$ is the smallest integer such that $\eta(n)!$ is divisible by $n$. In order to calculate it one considers, for each prime $p$, the associated function $\eta_{p}(n)$ in a power base. 
Florentin Smarandache