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A003593
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Numbers of the form 3^i*5^j.
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21
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1, 3, 5, 9, 15, 25, 27, 45, 75, 81, 125, 135, 225, 243, 375, 405, 625, 675, 729, 1125, 1215, 1875, 2025, 2187, 3125, 3375, 3645, 5625, 6075, 6561, 9375, 10125, 10935, 15625, 16875, 18225, 19683, 28125, 30375, 32805, 46875, 50625, 54675, 59049
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Odd 5-smooth numbers (A051037). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 18 2005
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
| a(n) =1/sqrt(15)*exp(sqrt(2*ln(3)*ln(5)*n)) asymptotically - Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 22 2002
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PROG
| (PARI) list(lim)=my(v=List(), N); for(n=0, log(lim)\log(5), N=5^n; while(N<=lim, listput(v, N); N*=3)); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jun 28 2011
(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a003593 n = a003593_list !! (n-1)
a003593_list = f (singleton 1) where
f s = m : f (insert (3*m) $ insert (5*m) s') where
(m, s') = deleteFindMin s
-- Reinhard Zumkeller, Sep 13 2011
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CROSSREFS
| Cf. A112751, A112752, A112753, A112754, A112755, A112756.
Cf. A033849, A143202.
Sequence in context: A057235 A057289 A056754 * A120027 A018586 A135342
Adjacent sequences: A003590 A003591 A003592 * A003594 A003595 A003596
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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