Primes p such that phi(p+1) = 2*phi(p-1) where phi = A000010.

Terms

a(0) =2a(1) =3a(2) =7a(3) =31a(4) =991a(5) =1951a(6) =2521a(7) =7411a(8) =23431a(9) =26731a(10) =37441a(11) =92431a(12) =131071a(13) =396631a(14) =489061a(15) =532141a(16) =830551a(17) =2811691a(18) =3319171a(19) =3698941a(20) =4247167a(21) =5239411a(22) =6829681a(23) =8326711a(24) =8997871a(25) =12625831a(26) =12889231a(27) =14756743a(28) =15891121a(29) =16125721