%I #14 Nov 09 2018 08:12:50
%S 1,13757837,6969969233,514208575135
%N Positive integers m such that 13^m == 12 (mod m).
%C No other terms below 10^15.
%C Some larger terms: 14551705803598782884189, 268766423508299769671017810348321281664525668552158231.
%o (PARI) is(n) = Mod(13, n)^n==12 \\ _Felix Fröhlich_, Nov 08 2018
%Y Solutions to 13^m == k (mod m): A001022 (k=0), A015963 (k=-1), A116621 (k=1), A116622 (k=2), A116629 (k=3), A116630 (k=4), A116611 (k=5), A116631 (k=6), A116632 (k=7), A295532 (k=8), A116636 (k=9), A116620(k=10), A116638 (k=11), this sequence (k=12), A321365 (k=14), A116639 (k=15).
%Y Cf. A116609, A127821, A128149.
%K nonn,more
%O 1,2
%A _Max Alekseyev_, Nov 07 2018
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