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A191138 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+1 and 4x+3 are in a.

%I A191138 #8 Jul 13 2013 12:04:10
%S A191138 1,4,7,13,19,22,31,40,55,58,67,79,91,94,121,127,163,166,175,202,223,
%T A191138 235,238,271,274,283,319,364,367,379,382,487,490,499,511,526,607,655,
%U A191138 667,670,703,706,715,811,814,823,850,895,943,955,958,1087,1093,1099,1102,1135,1138,1147,1279,1459,1462,1471,1498,1519,1531,1534
%N A191138 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 A191138 See A191113.
%H A191138 Reinhard Zumkeller, <a href="/A191138/b191138.txt">Table of n, a(n) for n = 1..10000</a>
%t A191138 h = 3; i = 1; j = 4; k = 3; f = 1; g = 9;
%t A191138 a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]   (* A191138 *)
%t A191138 b = (a - 1)/3; c = (a - 3)/4; r = Range[1, 1500];
%t A191138 d = Intersection[b, r] (* A191200 *)
%t A191138 e = Intersection[c, r] (* A191201 *)
%o A191138 (Haskell)
%o A191138 import Data.Set (singleton, deleteFindMin, insert)
%o A191138 a191138 n = a191138_list !! (n-1)
%o A191138 a191138_list = f $ singleton 1
%o A191138    where f s = m : (f $ insert (3*m+1) $ insert (4*m+3) s')
%o A191138              where (m, s') = deleteFindMin s
%o A191138 -- _Reinhard Zumkeller_, Jun 01 2011
%Y A191138 Cf. A191113.
%K A191138 nonn
%O A191138 1,2
%A A191138 _Clark Kimberling_, May 28 2011