1,1

6!-257=463;6!+257=977,...

lst={}; a=257; Do[If[PrimeQ[n!-a]&&PrimeQ[n!+a], AppendTo[lst, n]], {n, 2*5!}]; lst

Cf. A144046, A154660

Sequence in context: A085149 A007370 A044813 this_sequence A087753 A070762 A061208

Adjacent sequences: A154658 A154659 A154660 this_sequence A154662 A154663 A154664

nonn

Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 13 2009