cp's OEIS Frontend

A226371 Number of tilings of a 7 X n rectangle using integer-sided square tiles of area > 1.

%I A226371 #9 Sep 05 2021 21:59:39
%S A226371 1,0,0,0,0,0,7,1,0,0,2,0,57,16,1,0,32,4,463,197,29,1,392,100,3767,
%T A226371 2150,518,46,4267,1668,30763,21953,7454,1128,43531,23057,252755,
%U A226371 215070,94769,20728,426847,285548,2094102,2050219,1112227,321677,4080855,3290655
%N A226371 Number of tilings of a 7 X n rectangle using integer-sided square tiles of area > 1.
%H A226371 Alois P. Heinz, <a href="/A226371/b226371.txt">Table of n, a(n) for n = 0..1000</a>
%F A226371 G.f.: (-x^12-x^9+2*x^6+x^3-1) / (x^19 -x^18 -x^16 -x^15 -2*x^13 -7*x^12 +x^10 -8*x^9 +x^7 +9*x^6 +x^3-1).
%e A226371 a(10) = 2:
%e A226371 ._._._._._._._._._._.   ._._._._._._._._._._.
%e A226371 |         |         |   |   |   |   |   |   |
%e A226371 |         |         |   |___|___|___|___|___|
%e A226371 |         |         |   |         |         |
%e A226371 |         |         |   |         |         |
%e A226371 |_________|_________|   |         |         |
%e A226371 |   |   |   |   |   |   |         |         |
%e A226371 |___|___|___|___|___|   |_________|_________|
%p A226371 a:= n-> coeff(series((-x^12-x^9+2*x^6+x^3-1) / (x^19 -x^18 -x^16 -x^15 -2*x^13 -7*x^12 +x^10 -8*x^9 +x^7 +9*x^6 +x^3-1), x, n+1), x, n):
%p A226371 seq(a(n), n=0..70);
%Y A226371 Column k=7 of A226206.
%K A226371 nonn,easy
%O A226371 0,7
%A A226371 _Alois P. Heinz_, Jun 05 2013