1,1

Cf. A048161 Primes p such that p^2+1 is a semiprime.

Primes p such that (p^2+2)/3 is prime. For all primes q>3, we have q=6k+-1 for some k, which makes it easy to show that 3 divides q^2+2. Hence if q^2+2 is a semiprime then (q^2+2)/3 must be prime. - T. D. Noe (noe(AT)sspectra.com), May 05 2006

7 is ok because 7^2+2=51=3*17 (semiprime).

A109953=Select[Prime[Range[200]], Plus@@Last/@FactorInteger[ #^2+2]==2&]

Cf. A048161.

Cf. A118915 (primes p such that (p^2+5)/6 is prime).

Adjacent sequences: A109950 A109951 A109952 this_sequence A109954 A109955 A109956

Sequence in context: A019385 A075552 A124854 this_sequence A109417 A045372 A103776

nonn

Zak Seidov (zakseidov(AT)yahoo.com), Jul 06 2005