708256

Appears in sequences

• Number of n X n symmetric matrices with (0,1) entries and all row sums 2.at n=9A000986
• Number of n X n symmetric binary matrices with all row sums 7.at n=2A139674
• Number of 9 X 9 arrays of squares of integers, symmetric about main diagonal, with all rows summing to n.at n=2A156398
• 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=46A188448
• 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=47A333157
• 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=52A333157