A191126 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x and 4x-3 are in a.

1, 3, 9, 27, 33, 81, 99, 105, 129, 243, 297, 315, 321, 387, 393, 417, 513, 729, 891, 945, 963, 969, 1161, 1179, 1185, 1251, 1257, 1281, 1539, 1545, 1569, 1665, 2049, 2187, 2673, 2835, 2889, 2907, 2913, 3483, 3537, 3555, 3561, 3753, 3771, 3777, 3843, 3849, 3873, 4617, 4635, 4641, 4707, 4713, 4737, 4995, 5001, 5025, 5121

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 = -3; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191126 *)
b = a/3; c = (a + 3)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191176 *)
e = Intersection[c, r] (* A191177 *)
m = a/3   (* divisibility property *)
p = (a + 3)/6  (* divisibility property *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191126 n = a191126_list !! (n-1)
a191126_list = 1 : f (singleton 3)
   where f s = m : (f $ insert (3*m) $ insert (4*m-3) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011

Crossrefs

Cf. A191113.

Sequence in context: A061972 A029454 A095309 * A161141 A057238 A070364

Adjacent sequences: A191123 A191124 A191125 * A191127 A191128 A191129

Keyword

nonn

Author

Clark Kimberling, May 27 2011

Status

approved