Denoting by Γ the semigroup of
positive integers generated by two fixed primes, let rk(N) be the number of partitions
of N as a sum of k elements of Γ. Our main result is that r2(N) is a bounded
function of N. Incidentally, we obtain an estimate of the number of distinct prime
divisors of numbers of the form 1 + qn. Boundedness of rk(N) would resolve an
approximation theoretic conjecture of D. J. Newman.