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A006486
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a(n) = largest prime factor of n^n - 1.
(Formerly M2938)
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11
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3, 13, 17, 71, 43, 4733, 241, 757, 9091, 1806113, 20593, 1803647, 8108731, 39225301, 6700417, 2699538733, 465841, 109912203092239643840221, 222361, 227633407, 285451051007, 1920647391913, 1134793633, 50150933101, 3574533119, 12557612956332313, 1100860153
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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2,1
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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FORMULA
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MATHEMATICA
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Table[Max@Transpose[FactorInteger[n^n - 1]][[1]], {n, 2, 28}] (* Arkadiusz Wesolowski, Aug 06 2012 *)
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PROG
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(PARI) for(k=2, 28, my(x=factor(k^k-1), f=x[#x[, 1], 1]); print1(f, ", ")) \\ Hugo Pfoertner, Aug 23 2019
(Magma) [Max(PrimeDivisors(n^n-1)):n in [2..28]]; // Marius A. Burtea, Aug 24 2019
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CROSSREFS
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KEYWORD
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nonn,hard
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AUTHOR
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Dennis S. Kluk (mathemagician(AT)ameritech.net)
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EXTENSIONS
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Terms a(127)-a(138) in b-file added by Max Alekseyev, Aug 26 2021
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STATUS
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approved
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