919276domain: NAppears in sequencesEngel expansion for tan(1).at n=9A084652Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 4 6 or 7.at n=14A252551