819005domain: NAppears in sequencesApery (Apéry) numbers: Sum_{k=0..n} (binomial(n,k)*binomial(n+k,k))^2.at n=5A005259Crystal ball sequence for the A_5 x A_5 lattice.at n=5A143011Square array read by ascending antidiagonals: T(n,k) = [x^k] 1/(1 - x) * Legendre_P(k, (1 + x)/(1 - x))^n for n, k >= 0.at n=33A364113