A129932 Prime numbers p such that p remains prime through 6 iterations of function f(x) = 2x + 5.

541, 1861, 109111, 119101, 131617, 895351, 1774447, 2343037, 2906623, 3686743, 3686953, 4330783, 4594309, 4921129, 4922329, 5495989, 5654137, 6712591, 7093057, 7729537, 9188623, 9842263, 10492297, 10991983, 11270671, 12307453

Offset: 1

Author

Ray G. Opao, Jun 06 2007

Keywords

• nonn

Links

• Robert G. Wilson v, Table of a(n) for n = 1..149.

Crossrefs

Cf. A023332, A023304, A023274, A023243.

Programs

Mathematica

fQ[n_] := Union[PrimeQ /@ NestList[2 # + 5 &, n, 6]] == {True}; lst = {}; Do[ p = Prime@n; If[fQ@p, Print@p; AppendTo[lst, p]], {n, 10^7}]; lst (* Robert G. Wilson v *)
Select[Prime[Range[810000]],AllTrue[Rest[NestList[2#+5&,#,6]],PrimeQ]&] (* Harvey P. Dale, Mar 03 2025 *)

Extensions

More terms from Robert G. Wilson v, Jun 06 2007

Definition clarified by Harvey P. Dale, Mar 03 2025