A028464 Number of perfect matchings in graph C_{3} X C_{3} X P_{2n}.

1, 1120, 2861029, 7537209013, 19875272280736, 52411725012875905, 138211512392292291937, 364468498187098321751584, 961115930137025304064194421, 2534495671871264129163903449317, 6683552014192354263830206528781536, 17624755892139792658340655302347504609

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..250

Per Hakan Lundow, Computation of matching polynomials and the number of 1-factors in polygraphs, Research report, No 12, 1996, Department of Math., Umea University, Sweden.

Per Hakan Lundow, Enumeration of matchings in polygraphs, 1998.

Index entries for linear recurrences with constant coefficients, signature (2759,-325448,10121602,-125374286,684055000,-1622518920,1622518920,-684055000,125374286,-10121602,325448,-2759,1).

Formula

G.f.: -(x^12 -1639*x^11 +96397*x^10 -1989840*x^9 +17959907*x^8 -72515033*x^7 +117260158*x^6 -72515033*x^5 +17959907*x^4 -1989840*x^3 +96397*x^2 -1639*x +1) / (x^13 -2759*x^12 +325448*x^11 -10121602*x^10 +125374286*x^9 -684055000*x^8 +1622518920*x^7 -1622518920*x^6 +684055000*x^5 -125374286*x^4 +10121602*x^3 -325448*x^2 +2759*x -1). - Alois P. Heinz, Dec 09 2013

Crossrefs

Sequence in context: A234445 A222695 A032779 * A225995 A122052 A207234

Adjacent sequences: A028461 A028462 A028463 * A028465 A028466 A028467

Keyword

nonn,easy

Author

Per H. Lundow

Status

approved