OFFSET
1,1
COMMENTS
a(7^k-1) = 7^k.
LINKS
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
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Alexander Adamchuk, Jan 30 2007, Feb 05 2007
EXTENSIONS
a(5) from Joe K. Crump confirmed and a(6)-a(28) added by 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