49834domain: NAppears in sequencesNumber of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 1 3 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 1 3 6 or 7.at n=11A252298Composite numbers k such that phi(x) = psi(k)*phi(k) has no solution.at n=39A292714