This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A239267 #11 Aug 29 2015 02:14:49 %S A239267 1,21,1563,162409,17508475,1894621633,205109410835,22206188455913, %T A239267 2404176415007051,260291084969169553,28180738494571199683, %U A239267 3051022897700513626745,330322812747235906893563,35762812820215620676404385,3871905699058282397207463923 %N A239267 Number of domicule tilings of a 5 X 2n grid. %C A239267 A domicule is either a domino or it is formed by the union of two neighboring unit squares connected via their corners. In a tiling the connections of two domicules are allowed to cross each other. %H A239267 Alois P. Heinz, <a href="/A239267/b239267.txt">Table of n, a(n) for n = 0..450</a> %F A239267 G.f.: -(2048*x^7 -7680*x^6 -25472*x^5 +42048*x^4 -18928*x^3 +2912*x^2 -124*x+1) / (16384*x^8 -58112*x^7 -180608*x^6 +352480*x^5 -201552*x^4 +46976*x^3 -4394*x^2 +145*x-1). %p A239267 gf:= -(2048*x^7 -7680*x^6 -25472*x^5 +42048*x^4 -18928*x^3 +2912*x^2 -124*x+1) / (16384*x^8 -58112*x^7 -180608*x^6 +352480*x^5 -201552*x^4 +46976*x^3 -4394*x^2 +145*x-1): %p A239267 a:= n-> coeff(series(gf, x, n+1), x, n): %p A239267 seq(a(n), n=0..20); %Y A239267 Even bisection of column k=5 of A239264. %K A239267 nonn,easy %O A239267 0,2 %A A239267 _Alois P. Heinz_, Mar 13 2014