

A191131


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


9



1, 3, 7, 9, 15, 21, 27, 31, 39, 45, 63, 81, 87, 93, 111, 117, 127, 135, 159, 183, 189, 243, 255, 261, 279, 327, 333, 351, 375, 381, 405, 447, 471, 477, 511, 543, 549, 567, 639, 729, 735, 759, 765, 783, 837, 975, 981, 999, 1023, 1047, 1053, 1119, 1125, 1143, 1215, 1311, 1335, 1341, 1407, 1413, 1431, 1503, 1527, 1533, 1623
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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]]] (* A191131 *)
b = a/3; c = (a  3)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191186 *)
e = Intersection[c, r] (* A191187 *)


PROG

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191131 n = a191131_list !! (n1)
a191131_list = f $ singleton 1
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, A191186, A191187.
Note that A191131, A261524, A261871, and A282572 are very similar and easily confused with each other.
Sequence in context: A070993 A261524 A261871 * A282572 A299642 A128539
Adjacent sequences: A191128 A191129 A191130 * A191132 A191133 A191134


KEYWORD

nonn


AUTHOR

Clark Kimberling, May 27 2011


STATUS

approved



