2164680

Appears in sequences

• Number of (n+1)X(n+1) 0..5 arrays with diagonal zero and the i,j-th 2X2 subblock sum equal to the j,i-th 2X2 subblock sum.at n=2A187405
• T(n,k)=Number of (n+1)X(n+1) 0..k arrays with diagonal zero and the i,j-th 2X2 subblock sum equal to the j,i-th 2X2 subblock sum.at n=23A187408
• T(n,k) = number of n X n 0..k zero-diagonal arrays with corresponding row and column sums equal.at n=31A229417
• Number of 4X4 0..n zero-diagonal arrays with corresponding row and column sums equal.at n=4A229418
• a(n) = n! * Sum_{k=0..floor(n/2)} k^n/k!.at n=7A357191