  We study the Frobenius problem: given relatively prime positive integers
$a_1,...,a_d$, find the largest value of t (the Frobenius number) such that
$\sum_{k=1}^d m_k a_k = t$ has no solution in nonnegative integers
$m_1,...,m_d$. Based on empirical data, we conjecture that except for some
special cases the Frobenius number can be bounded from above by $\sqrt{a_1 a_2
a_3}^{5/4} - a_1 - a_2 - a_3$.
