A191121 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x-1 and 4x-1 are in a.

1, 2, 3, 5, 7, 8, 11, 14, 19, 20, 23, 27, 31, 32, 41, 43, 55, 56, 59, 68, 75, 79, 80, 91, 92, 95, 107, 122, 123, 127, 128, 163, 164, 167, 171, 176, 203, 219, 223, 224, 235, 236, 239, 271, 272, 275, 284, 299, 315, 319, 320, 363, 365, 367, 368, 379, 380, 383, 427, 487, 488, 491, 500, 507, 511, 512, 527, 608, 651, 655, 656, 667, 668

Offset

1,2

Comments

See A191113.

Links

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

Mathematica

h = 3; i = -1; j = 4; k = -1; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191121 *)
b = (a + 1)/3; c = (a + 1)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191166 *)
e = Intersection[c, r] (* A191167 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191121 n = a191121_list !! (n-1)
a191121_list = f $ singleton 1
   where f s = m : (f $ insert (3*m-1) $ insert (4*m-1) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011

Crossrefs

Cf. A191113, A191166, A191167.

Sequence in context: A190855 A190810 A278591 * A026401 A069353 A300163

Adjacent sequences: A191118 A191119 A191120 * A191122 A191123 A191124

Keyword

nonn

Author

Clark Kimberling, May 27 2011

Status

approved