77729

Appears in sequences

• Number of n X n binary matrices, symmetric under 90-degree rotation, with no more than 1 one in any 2 X 2 subblock.at n=12A141487
• a(n) = ( Sum_{k=0..n} binomial(2*n, k)^2 * (binomial(2*n, k+1) - binomial(2*n, k-1)) )/(n*binomial(2*n, n)).at n=5A259335
• Number of series-reduced plane trees with n leaves such that each branch directly under any given node has a different number of leaves.at n=10A319123