30670domain: NAppears in sequencesNumber of n X 4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 1 vertically.at n=9A207678Number of Dyck paths of semilength n such that no positive level has fewer than two peaks.at n=13A288678Number of principal reversible magic squares of order 4n.at n=54A308951