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A190810
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Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x+1 and 3x-1 are in a.
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4
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1, 2, 3, 5, 7, 8, 11, 14, 15, 17, 20, 23, 29, 31, 32, 35, 41, 44, 47, 50, 59, 63, 65, 68, 71, 83, 86, 89, 92, 95, 101, 104, 119, 122, 127, 131, 137, 140, 143, 149, 167, 173, 176, 179, 185, 188, 191, 194, 203, 209, 212, 239, 245, 248, 255, 257, 263, 266, 275, 281
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graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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See A190803.
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LINKS
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Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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MATHEMATICA
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h = 2; i = 1; j = 3; k = -1; f = 1; g = 9 ;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A190810 *)
b = (a - 1)/2; c = (a + 1)/3; r = Range[1, 900];
d = Intersection[b, r] (* A190855 *)
e = Intersection[c, r] (* A190856 *)
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PROG
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(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a190810 n = a190810_list !! (n-1)
a190810_list = f $ singleton 1
where f s = m : (f $ insert (2*m+1) $ insert (3*m-1) s')
where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011
(PARI) is(n)=if(n<7, n!=4, (n%3==1 && is(n\3)) || (n%2 && is(n\2))) \\ Charles R Greathouse IV, Jul 14 2016
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CROSSREFS
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Cf. A190803, A190855, A190856.
Sequence in context: A174895 A186285 A190855 * A278591 A191121 A026401
Adjacent sequences: A190807 A190808 A190809 * A190811 A190812 A190813
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KEYWORD
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nonn
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AUTHOR
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Clark Kimberling, May 20 2011
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EXTENSIONS
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a(55)=255 inserted by Reinhard Zumkeller, Jun 01 2011
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STATUS
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approved
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