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%I #18 Jul 07 2023 14:36:48
%S 1,9,94,1552,27285,509805,9783124
%N Building block is trapezoid formed from 3 equilateral triangles; sequence gives number of pieces (polytraps) that can be formed from n such trapezoids.
%C Also known as "Polytriamonds" because the building block is the unique triamond (composite of three equilateral triangles joined edge-to-edge). - _Aaron N. Siegel_, May 23 2022
%D Computed by Brendan Owen.
%H Abaroth's World, <a href="https://abarothsworld.com/Puzzles/Polyiamonds/Polyhes.htm">Polyhes, Polyhalfhexes & Polytriamonds</a>
%H Andrew Clarke, <a href="http://www.recmath.com/PolyPages/PolyPages/PolyX/PolyX.htm">Other Polyforms</a>
%Y Cf. A000577, A000228, A000105, A056844.
%K nonn,nice,hard,more
%O 1,2
%A _N. J. A. Sloane_, Oct 29 2000
%E Link updated by _William Rex Marshall_, Dec 16 2009
%E a(7) from _Aaron N. Siegel_, May 23 2022
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