A191127 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x and 4x-2 are in a.

1, 2, 3, 6, 9, 10, 18, 22, 27, 30, 34, 38, 54, 66, 70, 81, 86, 90, 102, 106, 114, 118, 134, 150, 162, 198, 210, 214, 243, 258, 262, 270, 278, 306, 318, 322, 342, 354, 358, 402, 406, 422, 450, 454, 470, 486, 534, 594, 598, 630, 642, 646, 729, 774, 786, 790, 810, 834, 838, 854, 918, 954, 966, 970, 1026, 1030, 1046, 1062, 1074, 1078

Offset

1,2

Comments

See A191113.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

h = 3; i = 0; j = 4; k = -2; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191127 *)
b = a/3; c = (a + 2)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191178 *)
e = Intersection[c, r] (* A191179 *)
Nest[Flatten[{#, 3#, 4#-2}]&, 1, 7]//Union (* Harvey P. Dale, Jul 20 2021 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191127 n = a191127_list !! (n-1)
a191127_list = f $ singleton 1
   where f s = m : (f $ insert (3*m) $ insert (4*m-2) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011

Crossrefs

Cf. A191119, A191178, A191179.

Sequence in context: A288930 A045588 A191178 * A015898 A157217 A058958

Adjacent sequences: A191124 A191125 A191126 * A191128 A191129 A191130

Keyword

nonn

Author

Clark Kimberling, May 27 2011

Status

approved