%I #10 Jan 05 2023 11:04:42
%S 0,0,0,0,0,0,0,1,2,16,70,378,1772,8456,38623,174400,771944,3378937
%N Number of free polyominoes of n cells with multiply-connected interiors.
%F a(n) = A000105(n) - A342537(n) (all free polyominoes minus simply-connected interior polyominoes).
%e a(8) = 1 because of:
%e OOO
%e O O
%e OOO
%Y Cf. A000104, A000105, A001419, A342537, A359520.
%K nonn,more
%O 1,9
%A _John Mason_, Jan 04 2023