12228193432domain: NAppears in sequencesProduct of two successive Catalan numbers C(n)*C(n+1).at n=11A005568a(n) = C(floor(n/2 + 1/2))*C(floor(n/2 + 1)) where C(i) = Catalan numbers A000108.at n=22A005817a(n) = floor(C(n/2)*C(n/2+1)), where C = Catalan numbers (A000108).at n=22A302093