2286648

Appears in sequences

• Number of distributive lattices; also number of paths with n turns when light is reflected from 9 glass plates.at n=8A030113
• a(n) = A050446(n, n) = A050447(n, n).at n=8A373659
• Triangle read by rows: T(n, k) = (-1)^k*binomial(n, k) * A050446(n, n - k).at n=36A373660