%N Number of planar n-hexes, or polyhexes (in the sense of A000228, so rotations and reflections count as the same shape) with at least one hole.
%C Apparently the same as the number of hexagonal planar circulenes (planar rings of hexagons) with n cells, although the two sequences may in fact differ for large n.
%D J. V. Knop et al., On the total number of polyhexes, Match, No. 16 (1984), 119-134.
%H Craig Knecht, <a href="/A038144/a038144.png">Tiling of a fixed pattern of holes in a frame.</a>
%H Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyomino, polyhex and polyiamond tiling</a>
%Y Cf. A018190, A038143, A038147, A000228, A018190.
%A _N. J. A. Sloane_
%E More terms from _Joseph Myers_, May 05 2002
%E Further terms from _Joseph Myers_, Nov 06 2003
%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 05 2007
%E Link edited by _Joseph Myers_, Nov 17 2010