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A046399
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Smallest squarefree palindrome with exactly n distinct prime factors.
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1
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1, 2, 6, 66, 858, 6006, 222222, 22444422, 244868442, 6434774346, 438024420834, 50146955964105, 2415957997595142, 495677121121776594
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Initial terms of sequences A046392-A046398.
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REFERENCES
| J.-P. Delahaye, Merveilleux nombres premiers ("Amazing primes"), p. 315, Pour la Science, Paris 2000.
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EXAMPLE
| a(4) = 2002 = 2*7*11*13.
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MATHEMATICA
| r[n_] := FromDigits[Reverse[IntegerDigits[n]]]; Do[k = 1; While[r[k] != k || !SquareFreeQ[k] || Length[Select[Divisors[k], PrimeQ]] != n, k++ ]; Print[k], {n, 0, 30}] - Ryan Propper (rpropper(AT)stanford.edu), Sep 16 2005
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CROSSREFS
| Cf. A046385.
Sequence in context: A070872 A055685 A082619 * A082617 A006517 A091458
Adjacent sequences: A046396 A046397 A046398 * A046400 A046401 A046402
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KEYWORD
| nonn,hard,base
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.
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EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), Dec 06 2008 at the suggestion of R. J. Mathar
a(10)-a(13) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 03 2011
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