%I #23 Feb 08 2024 01:47:43
%S 1,13,793,1943,150341,183793,2348789,26052527,27982637,54789869,
%T 1588344433,3928538029,8115802931,16936276919,17786709541,47778790033,
%U 973094452518029
%N Numbers m that divide 7^m + 6.
%C Conjecture: For k > 1, k^m == 1 - k (mod m) has infinite number of positive solutions.
%C Also includes 2073273696480171732497. - _Giovanni Resta_, Oct 04 2019
%o (Magma) [1] cat [n: n in [1..10^8] | Modexp(7, n, n) + 6 eq n];
%Y Solutions to k^m == 1-k (mod m): A006521 (k = 2), A015973 (k = 3), A327840 (k = 4), A123047 (k = 5), A327943 (k = 6), this sequence (k = 7), A327468 (k = 8).
%Y Cf. A253210 (7^n + 6).
%K nonn,more
%O 1,2
%A _Juri-Stepan Gerasimov_, Oct 02 2019
%E a(12)-a(16) from _Giovanni Resta_, Oct 04 2019
%E a(17) from _Max Alekseyev_, Feb 07 2024
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