475697854

Appears in sequences

• a(0) = 1, for n>=1, a(n) = Sum_{k=0..n} 9^k*N(n,k), where N(n,k) = (1/n)*C(n,k)*C(n,k+1) are the Narayana numbers (A001263).at n=9A082181
• a(n) = P(n, 1, -2*n-1, 1-2*n)/(n+1), P the Jacobi polynomial.at n=9A242369