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%I #36 Nov 29 2024 21:38:54
%S 2,2,6,11,6,2,6,11,6,2,6,11,6,2
%N Total number of coronal tilings for a width one length n straight polyiamond with the T2 triangle.
%C Heesch numbers look at the buildout of coronal layers from a single type of tile. In contrast this sequence looks at a single type of tile being asked to form a corona around an expanding central frame.
%C This central frame tiled with the hexiamond boat tile has a coronal expansion number of 12 (see links below).
%C A376899 shows coronal tilings for the expansion of a central triangle frame and gives the definition for the coronal expansion number.
%C Combining individual polyiamonds in various ways creates a variety of expansion frames._Craig Knecht_, Nov 29 2024
%H Craig Knecht, <a href="/A377978/a377978.png">example for the sequence</a>.
%H Craig Knecht, <a href="/A377978/a377978_3.png">Expansion frame worksheet.</a>
%H Craig Knecht, <a href="/A377978/a377978_1.png">Hexiamond boat corona</a>.
%Y Cf. A376899.
%K nonn,more
%O 1,1
%A _Craig Knecht_, Nov 26 2024