2747437056domain: NAppears in sequencesNumber of 6Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=21A208145a(n) is the least integer m such that A047994(m) = ((n-1)/n)*m where A047994 is the unitary totient function, or 0 if there is no such m.at n=24A318842