%I #10 Aug 20 2023 21:04:27
%S 5,13,19,173,5501
%N Numbers k such that 2^(k-1) == 1 (mod k) and 2^(k-1) == 3*k + 1 (mod k^2).
%Y Cf. A124924.
%K nonn,more
%O 1,1
%A _Alzhekeyev Ascar M_, Sep 30 2010
