A191125 - OEIS

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

%S 1,2,5,7,11,14,20,23,31,32,41,47,59,68,83,92,95,122,127,131,140,167,

%T 176,191,203,239,248,275,284,335,365,371,380,383,392,419,491,500,511,

%U 527,563,572,608,671,707,716,743,767,815,824,851,959,995,1004,1094,1103,1112,1139,1148,1175,1256,1343,1463,1472,1487,1499,1523

%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="/A191125/b191125.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[

%t   Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191125 *)

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

%t d = Intersection[b, r] (* A191174 *)

%t e = Intersection[c, r] (* A191175 *)

%o (Haskell)

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

%o a191125 n = a191125_list !! (n-1)

%o a191125_list = f $ singleton 1

%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