1,1

Primes of the form (-3 + n!!)/3 see A139057

a = {}; Do[If[PrimeQ[(-3 + n!!)/3], AppendTo[a, n]], {n, 1, 1000}]; a

Cf. A089085, A007749, A117141.

Adjacent sequences: A139053 A139054 A139055 this_sequence A139057 A139058 A139059

Sequence in context: A104236 A122781 A024904 this_sequence A120453 A022802 A074997

nonn

Artur Jasinski (grafix(AT)csl.pl), Apr 07 2008