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%I #9 Dec 09 2013 09:50:43
%S 1,22,1511,90040,5493583,334056618,20324827981,1236501116120,
%T 75226160041933,4576591071807054,278429681683117411,
%U 16939044773645481920,1030533959174319758227,62695402974582513118434,3814249420035058238741393,232050484511869215926762256
%N Number of matchings in graph P_{2} X P_{3} X P_{n}.
%D Per Hakan Lundow, "Computation of matching polynomials and the number of 1-factors in polygraphs", Research reports, No 12, 1996, Department of Mathematics, Umea University.
%H Alois P. Heinz, <a href="/A033526/b033526.txt">Table of n, a(n) for n = 0..500</a>
%H Per Hakan Lundow, <a href="http://www.theophys.kth.se/~phl/Text/1factors2.ps.gz">Enumeration of matchings in polygraphs</a>, 1998.
%F G.f.: (-x^22 +2*x^21 +105*x^20 -408*x^19 -2333*x^18 +11980*x^17 +12081*x^16 -112640*x^15 +25122*x^14 +435060*x^13 -292630*x^12 -741024*x^11 +647902*x^10 +512680*x^9 -535258*x^8 -85184*x^7 +168951*x^6 -24902*x^5 -12107*x^4 +3384*x^3 -57*x^2 -36*x +1) / (x^24 -4*x^23 -148*x^22 +636*x^21 +5486*x^20 -25774*x^19 -66616*x^18 +377290*x^17 +207927*x^16 -2210908*x^15 +370396*x^14 +5950068*x^13 -2989756*x^12 -7411696*x^11 +5362636*x^10 +3624000*x^9 -3734313*x^8 -139824*x^7 +897064*x^6 -240512*x^5 -5090*x^4 +7406*x^3 -292*x^2 -58*x +1). - _Alois P. Heinz_, Dec 09 2013
%K nonn
%O 0,2
%A _Per H. Lundow_
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