  We shall show that, for any positive integer $D>0$ and any primes $p_1, p_2$
not dividing $D$, the diophantine equation $x^2+D=2^s p_1^k p_2^l$ has at most
$63$ integer solutions $(x, k, l, s)$ with $x, k, l\geq 0$ and $s\in \{0, 2\}$.
