  We say that k is a P-integer if the first phi(k) primes coprime to k form a
reduced residue system modulo k. In 1980 Pomerance proved the finiteness of the
set of P-integers and conjectured that 30 is the largest P-integer. We prove
the conjecture assuming the Riemann Hypothesis. We further prove that there is
no P-integer between 30 and 10^11 and none above 10^3500.
