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A190807
Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x and 3x-1 are in a.
4
1, 2, 4, 5, 8, 10, 11, 14, 16, 20, 22, 23, 28, 29, 32, 40, 41, 44, 46, 47, 56, 58, 59, 64, 65, 68, 80, 82, 83, 86, 88, 92, 94, 95, 112, 116, 118, 119, 122, 128, 130, 131, 136, 137, 140, 160, 164, 166, 167, 172, 173, 176, 184, 188, 190, 191, 194, 203, 224, 232, 236, 238, 239, 244, 245, 248, 256, 257, 260, 262, 263, 272, 274, 275, 280
OFFSET
1,2
COMMENTS
See A190803.
LINKS
MATHEMATICA
h = 2; i = 0; j = 3; k = -1; f = 1; g = 9 ;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A190807 *)
b = a/2; c = (a + 1)/3; r = Range[1, 900];
d = Intersection[b, r] (* A190849 *)
e = Intersection[c, r] (* A190850 *)
PROG
(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a190807 n = a190807_list !! (n-1)
a190807_list = f $ singleton 1
where f s = m : (f $ insert (2*m) $ insert (3*m-1) s')
where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 20 2011
STATUS
approved