Middle members of prime triples {p, p+2, p+6}.

Terms

a(0) =7a(1) =13a(2) =19a(3) =43a(4) =103a(5) =109a(6) =193a(7) =229a(8) =313a(9) =349a(10) =463a(11) =643a(12) =823a(13) =859a(14) =883a(15) =1093a(16) =1279a(17) =1303a(18) =1429a(19) =1483a(20) =1489a(21) =1609a(22) =1873a(23) =1999a(24) =2083a(25) =2239a(26) =2269a(27) =2659a(28) =2689a(29) =3253