589569

Appears in sequences

• Triangle read by rows: T(n,k) is the number of fixed-point-free involutions of {1,2,...,2n} having k descents (n>=1; 1<=k<2n-1).at n=56A161127
• Number of n X 4 0..1 arrays with each 1 adjacent to 3 or 6 king-move neighboring 1s.at n=20A296309