68562444domain: NAppears in sequencesNumber of LEGO towers, one piece per floor, where every floor is perpendicular to the one below it (so we have a kind of 3-dimensional zigzag pattern).at n=16A082679Number of 0..3 arrays of length n with each element differing from at least one neighbor by 1 or less, starting with 0.at n=15A221678