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A190805 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x-1 and 3x+1 are in a. 3
1, 4, 7, 13, 22, 25, 40, 43, 49, 67, 76, 79, 85, 97, 121, 130, 133, 148, 151, 157, 169, 193, 202, 229, 238, 241, 256, 259, 265, 292, 295, 301, 313, 337, 364, 385, 391, 400, 403, 445, 454, 457, 472, 475, 481, 508, 511, 517, 529, 580, 583, 589, 601, 607, 625, 673, 688, 715, 724, 727 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
See A190803.
LINKS
MATHEMATICA
h = 2; i = -1; j = 3; k = 1; f = 1; g = 10 ;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A190805 *)
b = (a + 1)/2; c = (a - 1)/3; r = Range[1, 500];
d = Intersection[b, r] (* A190845 *)
e = Intersection[c, r] (* A190808 conjectured *)
PROG
(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a190805 n = a190805_list !! (n-1)
a190805_list = 1 : f (singleton 4)
where f s = m : (f $ insert (2*m-1) $ insert (3*m+1) s')
where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011
CROSSREFS
Sequence in context: A068940 A147487 A190845 * A008471 A156622 A111314
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 20 2011
EXTENSIONS
a(56)=673 inserted by Reinhard Zumkeller, Jun 01 2011
STATUS
approved

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Last modified February 25 02:17 EST 2024. Contains 370308 sequences. (Running on oeis4.)