142176

Appears in sequences

• a(n) = n*(n-1)*a(n-1)/2 + a(n-2), a(0) = a(1) = 1.at n=7A001046
• Number of (n+2) X (7+2) 0..3 arrays with every 3 X 3 subblock row and column sum equal to 0 2 3 6 or 7 and every 3 X 3 diagonal and antidiagonal sum not equal to 0 2 3 6 or 7.at n=8A252113