A350030 - OEIS

%I #20 Dec 11 2021 02:18:37

%S 1,1,2,4,11,27,82,250,815,2685,9072,30889,106290,367733,1279573,

%T 4470304,15676760,55147665

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

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

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

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

%K nonn,hard,more

%O 1,3

%A _John Mason_, Dec 09 2021