A191143 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+2 and 4x+1 are in a.

1, 5, 17, 21, 53, 65, 69, 85, 161, 197, 209, 213, 257, 261, 277, 341, 485, 593, 629, 641, 645, 773, 785, 789, 833, 837, 853, 1025, 1029, 1045, 1109, 1365, 1457, 1781, 1889, 1925, 1937, 1941, 2321, 2357, 2369, 2373, 2501, 2513, 2517, 2561, 2565, 2581, 3077, 3089, 3093, 3137, 3141, 3157, 3329, 3333, 3349, 3413, 4097, 4101

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 = 1; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191143 *)
b = (a - 2)/3; c = (a - 1)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191210 *)
e = Intersection[c, r] (* A191136 *)
m = (a + 1)/2 (* divisibility property *)
p = (a + 3)/4 (* divisibility property *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191143 n = a191143_list !! (n-1)
a191143_list = f $ singleton 1
   where f s = m : (f $ insert (3*m+2) $ insert (4*m+1) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011

Crossrefs

Cf. A191113.

Sequence in context: A305478 A262620 A191210 * A032376 A145818 A029986

Adjacent sequences: A191140 A191141 A191142 * A191144 A191145 A191146

Keyword

nonn

Author

Clark Kimberling, May 28 2011

Status

approved