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

References

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.

Links

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

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

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

Author

Per H. Lundow

Status

approved