102777312308domain: NAppears in sequencesNumber of distributive lattices; also number of paths with n turns when light is reflected from 5 glass plates.at n=20A006358Bottom line of 5-wave sequence A038201, also bisection of A006358.at n=10A038339Expansion of x + 1/(-x - 1/(-x - 1/(-x - 1/(-x - 1/(-x + 1))))).at n=20A373569