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A191132 Increasing sequence generated by these rules:  a(1)=1, and if x is in a then 3x+1 and 4x-3 are in a. 3
1, 4, 13, 40, 49, 121, 148, 157, 193, 364, 445, 472, 481, 580, 589, 625, 769, 1093, 1336, 1417, 1444, 1453, 1741, 1768, 1777, 1876, 1885, 1921, 2308, 2317, 2353, 2497, 3073, 3280, 4009, 4252, 4333, 4360, 4369, 5224, 5305, 5332, 5341, 5629, 5656, 5665, 5764, 5773, 5809, 6925, 6952, 6961, 7060, 7069, 7105, 7492, 7501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A191113.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

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

a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]   (* A191132 *)

b = (a - 1)/3; c = (a + 3)/4; r = Range[1, 2500];

d = Intersection[b, r] (* A191188 *)

e = Intersection[c, r] (* A191189 *)

PROG

(Haskell)

import Data.Set (singleton, deleteFindMin, insert)

a191132 n = a191132_list !! (n-1)

a191132_list = 1 : f (singleton 4)

   where f s = m : (f $ insert (3*m+1) $ insert (4*m-3) s')

             where (m, s') = deleteFindMin s

-- Reinhard Zumkeller, Jun 01 2011

CROSSREFS

Cf. A191113.

Sequence in context: A000746 A271012 A272581 * A119915 A137744 A027130

Adjacent sequences:  A191129 A191130 A191131 * A191133 A191134 A191135

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 27 2011

STATUS

approved

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Last modified November 17 20:44 EST 2018. Contains 317278 sequences. (Running on oeis4.)