166166domain: NAppears in sequencesExpansion of 1/((1+x)*(1-x)^7).at n=21A001769Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row and column sum not 1 3 6 or 8 and every diagonal and antidiagonal sum 1 3 6 or 8.at n=10A252047