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Search: id:A005937
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| A005937 |
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Pseudoprimes to base 6.
(Formerly M5246)
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+0
4
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| 35, 185, 217, 301, 481, 1105, 1111, 1261, 1333, 1729, 2465, 2701, 2821, 3421, 3565, 3589, 3913, 4123, 4495, 5713, 6533, 6601, 8029, 8365, 8911, 9331, 9881, 10585, 10621, 11041, 11137, 12209, 14315, 14701, 15841, 16589, 17329, 18361, 18721
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Theorem: If both numbers q and 2q-1 are primes and n=q*(2q-1) then 6^(n-1)==1 (mod n)(n is in the sequence) iff q is of the form 12k+1. 2701,18721,49141,104653,226801,665281,... are such terms. This sequence is a subsequence of A122783. - Farideh Firoozbakht (mymontain(AT)yahoo.com), Sep 12 2006
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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).
R. K. Guy, Unsolved Problems in Number Theory, A12.
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LINKS
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R. J. Mathar, Table of n, a(n) for n=1..118
Index entries for sequences related to pseudoprimes
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MATHEMATICA
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Select[Range[20000], ! PrimeQ[ # ] && Mod[6^(# - 1), # ] == 1 &] - Farideh Firoozbakht (mymontain(AT)yahoo.com), Sep 12 2006
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CROSSREFS
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Cf. A122783.
Sequence in context: A015219 A033851 A101954 this_sequence A007329 A101628 A064013
Adjacent sequences: A005934 A005935 A005936 this_sequence A005938 A005939 A005940
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Farideh Firoozbakht (mymontain(AT)yahoo.com), Sep 12 2006
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