Safe primes (A005385) (p and (p-1)/2 are primes) such that 6*p+1 is also prime.

Terms

a(0) =5a(1) =7a(2) =11a(3) =23a(4) =47a(5) =83a(6) =107a(7) =263a(8) =347a(9) =467a(10) =503a(11) =863a(12) =887a(13) =1283a(14) =1487a(15) =1823a(16) =1907a(17) =2027a(18) =2063a(19) =2447a(20) =2903a(21) =3203a(22) =3623a(23) =4007a(24) =4127a(25) =4547a(26) =4703a(27) =4787a(28) =5387a(29) =5807