211212domain: NAppears in sequencesList of subwords of A003842 arranged in lexicographic order.at n=25A213975List of words over {1,2} with equal numbers of 1's and 2's.at n=19A214218Number of length 4+1 0..n arrays with the sum of adjacent differences multiplied by some arrangement of +-1 equal to zero.at n=14A250169