By sifting the sequence of vectors (n, n + 2) (n integer), by playing
with the flexibility of the coefficients of the Rosser-Iwaniec sieve a
nd by inserting upperbounds (due to Deshouillers and Iwaniec) for sums
of Kloosterman sums, we improve some results concerning the set of in
tegers n such that n and n + 2 both have large prime factors only.