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A191119 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x-1 and 4x-3 are in a. 5

%I #10 Jul 13 2013 12:04:09

%S 1,2,5,14,17,41,50,53,65,122,149,158,161,194,197,209,257,365,446,473,

%T 482,485,581,590,593,626,629,641,770,773,785,833,1025,1094,1337,1418,

%U 1445,1454,1457,1742,1769,1778,1781,1877,1886,1889,1922,1925,1937,2309,2318,2321,2354,2357,2369,2498,2501,2513,2561,3074,3077

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

%C See A191113.

%H Reinhard Zumkeller, <a href="/A191119/b191119.txt">Table of n, a(n) for n = 1..10000</a>

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

%t a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191119 *)

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

%t d = Intersection[b, r] (* A191120 *)

%t e = Intersection[c, r] (* A191163 *)

%o (Haskell)

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

%o a191119 n = a191119_list !! (n-1)

%o a191119_list = 1 : f (singleton 2)

%o where f s = m : (f $ insert (3*m-1) $ insert (4*m-3) 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

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Last modified July 17 10:44 EDT 2024. Contains 374377 sequences. (Running on oeis4.)