1047717

Appears in sequences

• a(n) = (n-2)*a(n-1) - (n-1)*a(n-2), with a(0)=1, a(1)=1.at n=12A122092
• Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 1 vertically.at n=7A207372