A350030 a(n) is the number of n-celled unholey treelike polyominoes.

1, 1, 2, 4, 11, 27, 82, 250, 815, 2685, 9072, 30889, 106290, 367733, 1279573, 4470304, 15676760, 55147665

Offset: 1

Author

John Mason, Dec 09 2021

Keywords

• nonn
• hard
• more

Crossrefs

Cf. A308300 (number of simply connected square animals with n cells and k internal vertices, triangle read by rows).

Cf. A131482 (polyominoes with perimeter 2n+2, i.e., treelike).

Formula

a(n) = A308300(n,0).