233646504

Appears in sequences

• a(n) = (1/n)*Sum_{k=1..n} k*binomial(n,k-1)*binomial(2*n,n-k).at n=11A262394
• Number of North-East lattice paths from (0,0) to (n,n) that cross the diagonal y = x horizontally exactly three times.at n=11A268446