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%I #16 Mar 11 2024 23:11:11
%S 224,3108,9922,90176,401998,3113860,16091936,114557000,643041038,
%T 4357599552,25689719122,169094614280,1026275640544,6640849944580,
%U 40998347400722,262671237617216,1637828186763038,10433179552323108,65428999765032736,415409841636546440,2613799160004664798,16563343174199239744
%N Number of perfect matchings in the graph C_6 x C_n.
%H Seiichi Manyama, <a href="/A232804/b232804.txt">Table of n, a(n) for n = 3..500</a>
%H P. W. Kasteleyn, <a href="http://dx.doi.org/10.1016/0031-8914(61)90063-5">The Statistics of Dimers on a Lattice</a>, Physica, 27 (1961), 1209-1225.
%F G.f: 2*x^3*(112+882*x-8955*x^2-22184*x^3+151298*x^4+192108*x^5-1004174*x^6-773678*x^7+3077791*x^8+1598624*x^9-4646368*x^10-1738444*x^11+3589216*x^12+ 1010882*x^13-1408253*x^14-318388*x^15+271982*x^16+52648*x^17-23250*x^18-4062*x^19+601*x^20+100*x^21)/((1-x)*(1+x)*(1+5*x+x^2)*(1-5*x+x^2)*(1-2*x-x^2)* (1+2*x-x^2)*(1+x-x^2)*(1-x-x^2)*(1-5*x^2+x^4)*(1-6*x-3*x^2+6*x^3+x^4)).
%Y Row n=3 of A341741.
%Y Cf. A220864, A231087, A231485.
%K nonn
%O 3,1
%A _Sergey Perepechko_, Nov 30 2013
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