cp's OEIS Frontend

A191129 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x and 4x+1 are in a.

%I A191129 #8 Jul 13 2013 12:04:10
%S A191129 1,3,5,9,13,15,21,27,37,39,45,53,61,63,81,85,109,111,117,135,149,157,
%T A191129 159,181,183,189,213,243,245,253,255,325,327,333,341,351,405,437,445,
%U A191129 447,469,471,477,541,543,549,567,597,629,637,639,725,729,733,735,757,759,765,853,973,975,981,999,1013,1021,1023,1053,1215,1301
%N A191129 Increasing sequence generated by these rules:  a(1)=1, and if x is in a then 3x and 4x+1 are in a.
%C A191129 See A191113.
%H A191129 Reinhard Zumkeller, <a href="/A191129/b191129.txt">Table of n, a(n) for n = 1..10000</a>
%t A191129 h = 3; i = 0; j = 4; k = 1; f = 1; g = 9;
%t A191129 a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191129 *)
%t A191129 b = a/3; c = (a-1)/4; r = Range[1, 1500];
%t A191129 d = Intersection[b, r] (* A191182 *)
%t A191129 e = Intersection[c, r] (* A191183 *)
%o A191129 (Haskell)
%o A191129 import Data.Set (singleton, deleteFindMin, insert)
%o A191129 a191129 n = a191129_list !! (n-1)
%o A191129 a191129_list = f $ singleton 1
%o A191129    where f s = m : (f $ insert (3*m) $ insert (4*m+1) s')
%o A191129              where (m, s') = deleteFindMin s
%o A191129 -- _Reinhard Zumkeller_, Jun 01 2011
%Y A191129 Cf. A191113.
%K A191129 nonn
%O A191129 1,2
%A A191129 _Clark Kimberling_, May 27 2011