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A191121 Increasing sequence generated by these rules:  a(1)=1, and if x is in a then 3x-1 and 4x-1 are in a. 5
1, 2, 3, 5, 7, 8, 11, 14, 19, 20, 23, 27, 31, 32, 41, 43, 55, 56, 59, 68, 75, 79, 80, 91, 92, 95, 107, 122, 123, 127, 128, 163, 164, 167, 171, 176, 203, 219, 223, 224, 235, 236, 239, 271, 272, 275, 284, 299, 315, 319, 320, 363, 365, 367, 368, 379, 380, 383, 427, 487, 488, 491, 500, 507, 511, 512, 527, 608, 651, 655, 656, 667, 668 (list; graph; refs; listen; history; text; internal format)
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]]]  (* A191121 *)

b = (a + 1)/3; c = (a + 1)/4; r = Range[1, 1500];

d = Intersection[b, r] (* A191166 *)

e = Intersection[c, r] (* A191167 *)

PROG

(Haskell)

import Data.Set (singleton, deleteFindMin, insert)

a191121 n = a191121_list !! (n-1)

a191121_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, A191166, A191167.

Sequence in context: A186285 A190855 A190810 * A026401 A069353 A224858

Adjacent sequences:  A191118 A191119 A191120 * A191122 A191123 A191124

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 27 2011

STATUS

approved

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Last modified December 18 04:30 EST 2014. Contains 252079 sequences.