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