%I #20 Nov 11 2018 04:51:29
%S 1,6,24,200,3216
%N a(n) is the number of perimeter tiles among all rhombic tilings of the 2n-gon.
%C Tiles and polygons all have sides of length 1, as in A006245.
%H B. E. Tenner, <a href="https://arxiv.org/abs/1811.00082">Tiling-based models of perimeter and area</a>, arXiv:1811.00082 [math.CO], 2018.
%F a(n) = 2*n*A320945(n) for n > 2.
%e a(4) = 24 because among the eight rhombic tilings of the octagon, 24 perimeter rhombi appear.
%Y Cf. A320945, A320946, A006245.
%K nonn,more
%O 2,2
%A _Bridget Tenner_, Oct 24 2018