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

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

%S 1,7,19,31,55,79,91,127,163,223,235,271,319,367,379,487,511,655,667,

%T 703,811,895,943,955,1087,1099,1135,1279,1459,1471,1519,1531,1951,

%U 1963,1999,2047,2107,2431,2623,2671,2683,2815,2827,2863,3247,3259,3295,3403,3583,3775,3823,3835,4351,4375,4399,4411,4543,4555,4591

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

%C See A191113.

%H Reinhard Zumkeller, <a href="/A191118/b191118.txt">Table of n, a(n) for n = 1..10000</a>

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

%t a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191118 *)

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

%t d = Intersection[b, r] (* A191114 *)

%t e = Intersection[c, r] (* A191138 *)

%o (Haskell)

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

%o a191118 n = a191118_list !! (n-1)

%o a191118_list = 1 : f (singleton 7)

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

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Last modified September 23 16:16 EDT 2024. Contains 376178 sequences. (Running on oeis4.)