354864744877domain: NAppears in sequencesStrong pseudoprimes to bases 2, 3, 5 and 7.at n=4A074773a(A074773(n) mod 1519829 mod 18) = A074773(n), 1 <= n <= 18.at n=6A209834Twenty-seven smaller strong pseudoprimes to bases 2,3,5,7 arranged in order given by a function f:N->{1..27}.at n=19A210588