Primes p such that phi(p+1) = phi(p-1).

Terms

a(0) =5a(1) =11a(2) =71a(3) =911a(4) =1609a(5) =2591a(6) =4339a(7) =15401a(8) =58309a(9) =59149a(10) =80989a(11) =208391a(12) =215389a(13) =496511a(14) =589189a(15) =1809079a(16) =1970149a(17) =3167569a(18) =3260809a(19) =3516109a(20) =5914369a(21) =9832271a(22) =12231311a(23) =13608071a(24) =14470061a(25) =16537151a(26) =16692551a(27) =19018369a(28) =19462661