A191123 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, 5, 9, 14, 21, 26, 37, 41, 57, 62, 77, 85, 105, 110, 122, 149, 165, 170, 185, 229, 230, 249, 254, 309, 314, 329, 341, 365, 421, 441, 446, 489, 494, 509, 554, 597, 661, 681, 686, 689, 741, 746, 761, 917, 921, 926, 941, 986, 997, 1017, 1022, 1094, 1237, 1257, 1262, 1317, 1322, 1337, 1365, 1461, 1466, 1481, 1526, 1661, 1685

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]]]  (* A191123 *)
b = (a + 1)/3; c = (a - 1)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191170 *)
e = Intersection[c, r] (* A191171 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191123 n = a191123_list !! (n-1)
a191123_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: A024669 A006482 A191170 * A152888 A139423 A363459

Adjacent sequences: A191120 A191121 A191122 * A191124 A191125 A191126

Keyword

nonn

Author

Clark Kimberling, May 27 2011

Status

approved