199570

Appears in sequences

• Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and two or three distinct values.at n=9A211816
• Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 2 3 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 2 3 6 or 7.at n=25A252257