265730domain: NAppears in sequencesNumber of self-avoiding walks of n steps on a Manhattan square lattice.at n=21A117633Number of (n+2) X (7+2) 0..3 arrays with every 3 X 3 subblock row and column sum not 2 3 6 or 7 and every diagonal and antidiagonal sum 2 3 6 or 7.at n=9A251893