A129931 Numbers n such that n remains prime through 7 iterations of function f(x) = 2x + 5.

4594309, 4921129, 5495989, 7093057, 14722021, 23008891, 23380471, 24251167, 24296563, 49201981, 51788797, 62123011, 64649503, 69326779, 78274321, 88022797, 95575771, 100099267, 125796127, 128185777, 129299011, 130858711

Offset: 1

Author

Ray G. Opao, Jun 06 2007

Keywords

• nonn

Crossrefs

Cf. A023243, A023274, A023304, A023332.

Programs

Mathematica

fQ[n_] := Union[PrimeQ /@ NestList[2 # + 5 &, n, 7]] == {True}; lst = {}; Do[ p = Prime@n; If[fQ@p, Print@p; AppendTo[lst, p]], {n, 10^7}]; lst (* Robert G. Wilson v *)

Extensions

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