Primes of the form 2*k*prime(k) + 1.

Terms

a(0) =5a(1) =13a(2) =31a(3) =157a(4) =239a(5) =683a(6) =1697a(7) =3067a(8) =4273a(9) =5563a(10) =6323a(11) =6781a(12) =9043a(13) =13841a(14) =16427a(15) =22247a(16) =22901a(17) =23767a(18) =27109a(19) =32687a(20) =33721a(21) =45833a(22) =58217a(23) =61933a(24) =83341a(25) =90583a(26) =94811a(27) =115979a(28) =158161a(29) =172751