1,2

14*1-1=13, 14*3-1=41, 14*6-1=83, ...

a={}; Do[x=14*n-1; If[PrimeQ[x], AppendTo[a, n]], {n, 10^2}]; a

Sequence in context: A165496 A087249 A091087 this_sequence A080147 A084463 A096604

Adjacent sequences: A138619 A138620 A138621 this_sequence A138623 A138624 A138625

nonn

Vladimir Orlovsky (4vladimir(AT)gmail.com), May 14 2008