A191136 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, 4, 5, 13, 16, 17, 21, 40, 49, 52, 53, 64, 65, 69, 85, 121, 148, 157, 160, 161, 193, 196, 197, 208, 209, 213, 256, 257, 261, 277, 341, 364, 445, 472, 481, 484, 485, 580, 589, 592, 593, 625, 628, 629, 640, 641, 645, 769, 772, 773, 784, 785, 789, 832, 833, 837, 853, 1024, 1025, 1029, 1045, 1093, 1109, 1336, 1365, 1417, 1444

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]]]   (* A191136 *)
b = (a - 1)/3; c = (a - 1)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191196 *)
e = Intersection[c, r] (* A191197 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191136 n = a191136_list !! (n-1)
a191136_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.

Sequence in context: A087882 A338544 A191196 * A083709 A091183 A234254

Adjacent sequences: A191133 A191134 A191135 * A191137 A191138 A191139

Keyword

nonn

Author

Clark Kimberling, May 28 2011

Status

approved