39856

Appears in sequences

• G.f.: ( 1 - x^2 - sqrt( 1 - 2*x^2 - 4*x^3 - 3*x^4 ) ) / ( 2*x^3 ).at n=19A050253
• Number of permutations of {1,...,n} avoiding adjacent step pattern up, down, down, down, down, up.at n=8A177535
• Number of unlabeled 2,3 cacti (triangular cacti with bridges) rooted at a triangle with n triangles and every node contained in exactly one triangle.at n=9A381469