26946809137domain: NAppears in sequencesNumbers k such that 2^(2^k-2) == 1 (mod k^2) and 2^(k-1) =/= 1 (mod k).at n=21A374953Numbers k such that 2^(2^(k-1)-1) == 1 (mod k^2) and 2^(k-1) =/= 1 (mod k).at n=7A376473