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A191135 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+1 and 4x are in a. 3

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

%S 1,4,13,16,40,49,52,64,121,148,157,160,193,196,208,256,364,445,472,

%T 481,484,580,589,592,625,628,640,769,772,784,832,1024,1093,1336,1417,

%U 1444,1453,1456,1741,1768,1777,1780,1876,1885,1888,1921,1924,1936,2308,2317,2320,2353,2356,2368,2497,2500,2512,2560,3073,3076

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

%C See A191113.

%H Reinhard Zumkeller, <a href="/A191135/b191135.txt">Table of n, a(n) for n = 1..10000</a>

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

%t a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191135 *)

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

%t d = Intersection[b, r] (* A191136 *)

%t e = Intersection[c, r] (* A191195 *)

%o (Haskell)

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

%o a191135 n = a191135_list !! (n-1)

%o a191135_list = f $ singleton 1

%o where f s = m : (f $ insert (3*m+1) $ insert (4*m) 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 28 2011

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Last modified April 25 01:35 EDT 2024. Contains 371964 sequences. (Running on oeis4.)