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%I #11 Dec 04 2023 01:35:35
%S 6,48,592,8664,140088,2414056
%N Number of fixed (4,2)-polyominoids with n cells, allowing right-angled (or hard) connections only.
%C Two squares sharing an edge have a right-angled connection if they do not lie in the same plane.
%C Connections that are not right-angled (flat connections) may occur, but the polyominoids considered here must be connected through right-angled connections only.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Polyominoid">Polyominoid</a>.
%H <a href="/index/Pol#polyominoes">Index entries for sequences related to polyominoes</a>.
%Y Cf. A075678, A365655, A366335, A366338 (free), A366341.
%Y 45th row of A366767.
%K nonn,hard,more
%O 1,1
%A _Pontus von Brömssen_, Oct 07 2023