1944530

Appears in sequences

• Number of n X n symmetric binary matrices with all row sums 4.at n=4A139670
• T(n,k)=Number of (n*k)Xk binary arrays with nonzero rows in decreasing order, no more than 2 ones in any row and exactly n ones in every column.at n=58A188448
• Number of n X n 0..1 symmetric arrays with every row summing to floor(n/2).at n=8A213793
• T(n,k)=Number of n X n 0..k symmetric arrays with every row summing to floor(n*k/2).at n=35A213800
• Triangle read by rows: T(n,k) is the number of n X n symmetric binary matrices with k ones in every row and column.at n=40A333157
• Number of 2n X 2n symmetric matrices with entries in {+1, -1} and all rows and columns summing to zero.at n=4A333164