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A191117 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x-2 and 4x+2 are in a. 4

%I #14 Jul 13 2013 12:04:09

%S 1,6,16,26,46,66,76,106,136,186,196,226,266,306,316,406,426,546,556,

%T 586,676,746,786,796,906,916,946,1066,1216,1226,1266,1276,1626,1636,

%U 1666,1706,1756,2026,2186,2226,2236,2346,2356,2386,2706,2716,2746,2836,2986,3146,3186,3196,3626,3646,3666,3676,3786,3796,3826

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

%C See A191113.

%H Reinhard Zumkeller, <a href="/A191117/b191117.txt">Table of n, a(n) for n = 1..10000</a>

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

%t a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191117 *)

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

%t d = Intersection[b, r] (* A191157 *)

%t e = Intersection[c, r] (* A191158 *)

%t m = (a + 4)/10 (* divisibility property *)

%o (Haskell)

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

%o a191117 n = a191117_list !! (n-1)

%o a191117_list = 1 : f (singleton 6)

%o where f s = m : (f $ insert (3*m-2) $ 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

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Last modified April 23 16:40 EDT 2024. Contains 371916 sequences. (Running on oeis4.)