A191140 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+2 and 4x-2 are in a.

1, 2, 5, 6, 8, 17, 18, 20, 22, 26, 30, 53, 56, 62, 66, 68, 70, 78, 80, 86, 92, 102, 118, 161, 170, 188, 200, 206, 210, 212, 222, 236, 242, 246, 260, 262, 270, 278, 308, 310, 318, 342, 356, 366, 406, 470, 485, 512, 566, 602, 620, 632, 638, 642, 668, 678, 710, 728, 740, 750, 782, 788, 798, 812, 822, 836, 838, 846, 886, 926, 932, 942

Offset

1,2

Comments

See A191113.

Links

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

Mathematica

h = 3; i = 2; j = 4; k = -2; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191140 *)
b = (a - 2)/3; c = (a + 2)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191204 *)
e = Intersection[c, r] (* A191205 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191140 n = a191140_list !! (n-1)
a191140_list = f $ singleton 1
   where f s = m : (f $ insert (3*m+2) $ insert (4*m-2) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011

Crossrefs

Cf. A191113.

Sequence in context: A242665 A079256 A191204 * A271430 A326854 A097685

Adjacent sequences: A191137 A191138 A191139 * A191141 A191142 A191143

Keyword

nonn

Author

Clark Kimberling, May 28 2011

Status

approved