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A191127
Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x and 4x-2 are in a.
4
1, 2, 3, 6, 9, 10, 18, 22, 27, 30, 34, 38, 54, 66, 70, 81, 86, 90, 102, 106, 114, 118, 134, 150, 162, 198, 210, 214, 243, 258, 262, 270, 278, 306, 318, 322, 342, 354, 358, 402, 406, 422, 450, 454, 470, 486, 534, 594, 598, 630, 642, 646, 729, 774, 786, 790, 810, 834, 838, 854, 918, 954, 966, 970, 1026, 1030, 1046, 1062, 1074, 1078
OFFSET
1,2
COMMENTS
See A191113.
LINKS
MATHEMATICA
h = 3; i = 0; j = 4; k = -2; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191127 *)
b = a/3; c = (a + 2)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191178 *)
e = Intersection[c, r] (* A191179 *)
Nest[Flatten[{#, 3#, 4#-2}]&, 1, 7]//Union (* Harvey P. Dale, Jul 20 2021 *)
PROG
(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191127 n = a191127_list !! (n-1)
a191127_list = f $ singleton 1
where f s = m : (f $ insert (3*m) $ insert (4*m-2) s')
where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 27 2011
STATUS
approved