A028477 Number of perfect matchings in graph C_{6} X P_{n}.

1, 2, 20, 108, 725, 4480, 28561, 179928, 1138660, 7193450, 45474461, 287400960, 1816564229, 11481464878, 72568802500, 458669938608, 2899021855801, 18323243845760, 115811947027949, 731988596166300, 4626528972901940, 29241944603930518, 184823511249946969

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

Table of n, a(n) for n=0..22.

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

Formula

G.f.: -(x^4 +2*x^3 -4*x^2 -2*x +1) / (x^6 +4*x^5 -16*x^4 -6*x^3 +16*x^2 +4*x -1).

Crossrefs

Sequence in context: A009357 A052361 A001884 * A073077 A069537 A282818

Adjacent sequences: A028474 A028475 A028476 * A028478 A028479 A028480

Keyword

nonn

Author

Per H. Lundow

Status

approved