A190807 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x and 3x-1 are in a.

1, 2, 4, 5, 8, 10, 11, 14, 16, 20, 22, 23, 28, 29, 32, 40, 41, 44, 46, 47, 56, 58, 59, 64, 65, 68, 80, 82, 83, 86, 88, 92, 94, 95, 112, 116, 118, 119, 122, 128, 130, 131, 136, 137, 140, 160, 164, 166, 167, 172, 173, 176, 184, 188, 190, 191, 194, 203, 224, 232, 236, 238, 239, 244, 245, 248, 256, 257, 260, 262, 263, 272, 274, 275, 280

Offset

1,2

Comments

See A190803.

Links

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

Mathematica

h = 2; i = 0; j = 3; k = -1; f = 1; g = 9 ;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A190807 *)
b = a/2; c = (a + 1)/3; r = Range[1, 900];
d = Intersection[b, r] (* A190849 *)
e = Intersection[c, r] (* A190850 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a190807 n = a190807_list !! (n-1)
a190807_list = f $ singleton 1
   where f s = m : (f $ insert (2*m) $ insert (3*m-1) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011

Crossrefs

Cf. A190803, A190849, A190850.

Sequence in context: A284880 A047261 A286687 * A289058 A102798 A247886

Adjacent sequences: A190804 A190805 A190806 * A190808 A190809 A190810

Keyword

nonn

Author

Clark Kimberling, May 20 2011

Status

approved