77884

Appears in sequences

• Number of polyiamonds with n cells that tile the plane by 180-degree rotation (Conway criterion).at n=17A075220
• Number of ways to place zero or more nonadjacent 1,0 1,1 2,0 3,0 4,0 5,0 6,1 polyhexes in any orientation on a planar nXnXn triangular grid.at n=8A155331
• G.f. satisfies A(x) = 1 + x/(1 + x^3) * A(x/(1 + x^3)).at n=19A360898