A153776 Sequence S such that 1 is in S and if x is in S, then 5x-3 and 5x-1 are in S.

1, 2, 4, 7, 9, 17, 19, 32, 34, 42, 44, 82, 84, 92, 94, 157, 159, 167, 169, 207, 209, 217, 219, 407, 409, 417, 419, 457, 459, 467, 469, 782, 784, 792, 794, 832, 834, 842, 844, 1032, 1034, 1042, 1044, 1082, 1084, 1092, 1094, 2032, 2034, 2042, 2044, 2082, 2084

Offset: 1

Author

Clark Kimberling, Jan 02 2009

Keywords

• nonn

Comments

Subsequences include A047850, A083065.

First generation: 1

2nd generation: 2, 4

3rd generation: 7, 9, 17, 19

4th generation: 32, 34, 42, 44, 82, 84, 92, 94

Does every generation contain p or 2p for some prime p?

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A047850, A083065, A153773, A153775.

Programs

Mathematica

nxt[n_] := Flatten[5 # + {-3, -1} & /@ n]; Union[Flatten[NestList[nxt, {1}, 5]]] (* G. C. Greubel, Aug 28 2016 *)