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

%I #8 Jul 13 2013 12:04:10

%S 1,3,6,9,14,18,26,27,38,42,54,58,74,78,81,106,110,114,126,154,162,170,

%T 174,218,222,234,243,298,314,318,326,330,342,378,426,442,458,462,486,

%U 506,510,522,618,650,654,666,682,698,702,729,874,890,894,938,942,954,974,978,990,1026,1134,1194,1258,1274,1278,1306,1322,1326

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

%C See A191113.

%H Reinhard Zumkeller, <a href="/A191130/b191130.txt">Table of n, a(n) for n = 1..10000</a>

%t h = 3; i = 0; j = 4; k = 2; f = 1; g = 9;

%t a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191130 *)

%t b = a/3; c = (a - 2)/4; r = Range[1, 1500];

%t d = Intersection[b, r] (* A191184 *)

%t e = Intersection[c, r] (* A191185 *)

%o (Haskell)

%o import Data.Set (singleton, deleteFindMin, insert)

%o a191130 n = a191130_list !! (n-1)

%o a191130_list = f $ singleton 1

%o where f s = m : (f $ insert (3*m) $ insert (4*m+2) s')

%o where (m, s') = deleteFindMin s

%o -- _Reinhard Zumkeller_, Jun 01 2011

%Y Cf. A191113.

%K nonn

%O 1,2

%A _Clark Kimberling_, May 27 2011