Let $B_p$ denote Pascal's triangle modulo $p$, i.e. $B_p(x,
y)={x+y\choose x} \MOD p$ and let $\Pow_p$ denote the set of $e$-th
powers. For all pairs $(p,e)$, $2\le p \le 20$, $2\le e \le 20$
except $p=2$, $e>2$ even and $p=3$, $e=9,18$ the operations $+$,
$\times$ are first order definable in $\strN{B_p,\Powe}$. In the
mentioned exceptional cases the operations $+$, $\times$ are not
definable.
