1764648domain: NAppears in sequencesNumber of subsets A of {1..n} such that there are no solutions to a+b+c=d for a,b,c,d in A.at n=29A093970Number of (n+2)X(6+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 1 3 6 or 7.at n=12A252190