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%I #31 Aug 20 2021 04:22:07
%S 1,2,4,14,628,11524,16814,188404,441484,2541014,3984724,172315684,
%T 208268941,40874725514,280454588548,489850370956,1235856817732,
%U 62479203805793,95467808763364,116016015619396,396249210287836
%N Numbers k that divide 5^k + 3.
%C No other terms below 10^15. A larger term: 783847656467936404. - _Max Alekseyev_, Oct 16 2016
%t Select[Range[1000000], IntegerQ[(PowerMod[5,#,# ]+3)/# ]&]
%o (PARI) is(n)=Mod(5,n)^n==-3 \\ _Charles R Greathouse IV_, Apr 06 2014
%Y Solutions to 5^n == k (mod n): A067946 (k=1), A015951 (k=-1), A124246 (k=2), A123062 (k=-2), A123061 (k=3), this sequence (k=-3), A125949 (k=4), A123047 (k=-4), A123091 (k=5), A015891 (k=-5), A277350 (k=6), A277348 (k=-6).
%K hard,nonn
%O 1,2
%A _Alexander Adamchuk_, Nov 04 2006
%E a(10)-a(13) from _Ryan Propper_, Dec 30 2006, Jan 02 2007
%E More terms from _Lars Blomberg_, Nov 25 2011
%E Terms a(14) onwards were reported incorrect by _Toshitaka Suzuki_, and have been deleted. - _N. J. A. Sloane_, Mar 18 2014
%E a(14)-a(17) from _Toshitaka Suzuki_, Mar 18 2014, Apr 03 2014
%E a(18)-a(21) from _Max Alekseyev_, Oct 16 2016
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