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A191143
Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+2 and 4x+1 are in a.
4
1, 5, 17, 21, 53, 65, 69, 85, 161, 197, 209, 213, 257, 261, 277, 341, 485, 593, 629, 641, 645, 773, 785, 789, 833, 837, 853, 1025, 1029, 1045, 1109, 1365, 1457, 1781, 1889, 1925, 1937, 1941, 2321, 2357, 2369, 2373, 2501, 2513, 2517, 2561, 2565, 2581, 3077, 3089, 3093, 3137, 3141, 3157, 3329, 3333, 3349, 3413, 4097, 4101
OFFSET
1,2
COMMENTS
See A191113.
LINKS
MATHEMATICA
h = 3; i = 2; j = 4; k = 1; f = 1; g = 9;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191143 *)
b = (a - 2)/3; c = (a - 1)/4; r = Range[1, 1500];
d = Intersection[b, r] (* A191210 *)
e = Intersection[c, r] (* A191136 *)
m = (a + 1)/2 (* divisibility property *)
p = (a + 3)/4 (* divisibility property *)
PROG
(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a191143 n = a191143_list !! (n-1)
a191143_list = f $ singleton 1
where f s = m : (f $ insert (3*m+2) $ insert (4*m+1) s')
where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011
CROSSREFS
Cf. A191113.
Sequence in context: A305478 A262620 A191210 * A032376 A145818 A029986
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 28 2011
STATUS
approved