Primes of the form (p^2+p+1)/3 where p is prime.

Terms

a(0) =19a(1) =61a(2) =127a(3) =331a(4) =631a(5) =1801a(6) =3169a(7) =3571a(8) =5419a(9) =8269a(10) =13267a(11) =16651a(12) =19441a(13) =24571a(14) =55897a(15) =59221a(16) =145861a(17) =151201a(18) =176419a(19) =246247a(20) =260191a(21) =292969a(22) =347821a(23) =360187a(24) =368551a(25) =377011a(26) =398581a(27) =698419a(28) =733591a(29) =863497