223292domain: NAppears in sequencesa(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026637.at n=8A026968Number of n X 2 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor.at n=16A201533