Number of convex permutominoes of size n.

Terms

a(0) =1a(1) =4a(2) =18a(3) =84a(4) =394a(5) =1836a(6) =8468a(7) =38632a(8) =174426a(9) =780156a(10) =3460156a(11) =15232344a(12) =66613828a(13) =289609144a(14) =1252537704a(15) =5391904208a(16) =23114020090a(17) =98712408732a(18) =420134237996