Primes that remain prime through 4 iterations of function f(x) = 2x + 3.

Terms

a(0) =47a(1) =67a(2) =97a(3) =137a(4) =307a(5) =1427a(6) =2857a(7) =6047a(8) =6997a(9) =9377a(10) =12097a(11) =16057a(12) =24197a(13) =32117a(14) =35117a(15) =36877a(16) =44507a(17) =46687a(18) =54517a(19) =55487a(20) =64877a(21) =71327a(22) =71807a(23) =76537a(24) =89017a(25) =92387a(26) =94427a(27) =100057a(28) =132707a(29) =142057