182116domain: NAppears in sequencesa(n) = (n^4 + 46*n^3 - 169*n^2 + 146*n + 24)/24.at n=36A143059Number of free tetrakis polyaboloes (poly-[4.8^2]-tiles) with n cells, allowing holes, where division into tetrakis cells (triangular quarters of square grid cells) is significant.at n=15A197465