OFFSET
0,2
COMMENTS
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.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
FORMULA
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).
MAPLE
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):
a:= n-> coeff(series(gf, x, n+1), x, n):
seq(a(n), n=0..20);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Mar 13 2014
STATUS
approved