250425

Appears in sequences

• Triangular array read by rows: T(n, k) = S(n, [n/2]-k) and S(n,k) = C(n, 2*k)*(2*k-1)!!*((2*k-1)!! + 1)/2, n>=0, 0<=k<=[n/2].at n=31A246257
• a(n) = Sum_{k=0..floor(n/5)} binomial(n+4,5*k+4) * Catalan(k).at n=16A360047