A145409 - OEIS

%I #6 Jan 01 2019 06:31:05

%S 15,376,8805,207901,4903920,115686901,2729093235,64380355576,

%T 1518756918825,35828050696201,845197277027040,19938523685081401,

%U 470357320740846855,11095907233164566776,261756651587724670845

%N Number of perfect matchings (or domino tilings) in K_6 X P_n.

%D F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Ars Combin. 49 (1998), 129-154.

%H F. Faase, <a href="http://www.iwriteiam.nl/Cpaper.zip">On the number of specific spanning subgraphs of the graphs G X P_n</a>, Preliminary version of paper that appeared in Ars Combin. 49 (1998), 129-154.

%H F. Faase, <a href="http://www.iwriteiam.nl/counting.html">Counting Hamiltonian cycles in product graphs</a>.

%H F. Faase, <a href="http://www.iwriteiam.nl/Cresults.html">Results from the counting program</a>

%F Recurrence:

%F a(1) = 15,

%F a(2) = 376,

%F a(3) = 8805,

%F a(4) = 207901, and

%F a(n) = 21a(n-1) + 62a(n-2) - 21a(n-3) - a(n-4).

%F G.f.: x(15+61x-21x^2-x^3)/(1-21x-62x^2+21x^3+x^4). - _R. J. Mathar_, Feb 19 2009

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Feb 03 2009

%E More terms from _R. J. Mathar_, Feb 19 2009