Almost-convex polygons of perimeter 2n on square lattice.

A007221

Almost-convex polygons of perimeter 2n on square lattice.

Terms

    a(0) =6a(1) =216a(2) =3706a(3) =44060a(4) =417486a(5) =3386912a(6) =24554562a(7) =163587572a(8) =1020918342a(9) =6050527496a(10) =34395992698a(11) =188971062108

External references