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A127816
a(n) = least k >= 1 such that the remainder when 6^k is divided by k is n.
38
5, 34, 213, 68, 4021227877, 7, 121129, 14, 69, 26, 767, 51, 6191, 22, 201, 20, 1919, 33, 169, 44, 39, 1778, 1926049, 174, 2673413, 50, 63, 451, 1257243481237, 93, 851, 316, 183, 14809, 1969, 38, 1362959, 1826, 177, 289, 65, 87, 5567, 1252, 57, 1651, 6403249
OFFSET
1,1
COMMENTS
a(7^k-1) = 7^k.
FORMULA
a(7^k-1) = 7^k.
MATHEMATICA
t = Table[0, {10000}]; k = 1; lst = {}; While[k < 5600000000, a = PowerMod[6, k, k]; If[ a<10001 && t[[a]]==0, t[[a]]=k; Print[{a, k}]]; k++ ]; t
KEYWORD
hard,nonn
AUTHOR
Alexander Adamchuk, Jan 30 2007, Feb 05 2007
EXTENSIONS
a(5) <= 20866130267 from Max Alekseyev, Feb 06 2007
a(5) <= 4021227877 from Joe K. Crump (joecr(AT)carolina.rr.com), Feb 10 2007
a(29) <= 1257243481237 from Joe K. Crump (joecr(AT)carolina.rr.com), Feb 09 2007
a(5) through a(28) from Ryan Propper, Feb 21 2007
I combined the two Mathematica codings into one and extended the search limits Robert G. Wilson v, Jul 16 2009
a(29) as conjectured by J. K. Crump confirmed by Hagen von Eitzen, Jul 21 2009
Corrected authorship of the a-file - R. J. Mathar, Aug 24 2009
STATUS
approved