218342domain: NAppears in sequencesNumber of 4n-step self-avoiding closed paths on first quadrant grid, passing through origin, symmetric about line y = x.at n=10A038393Number of (n+2)X(6+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00001001 or 00100101.at n=9A260978