A028455 Number of perfect matchings in graph P_{2} X C_{3} X P_{n}.

1, 4, 50, 444, 4349, 41348, 396733, 3795912, 36350866, 348013000, 3332060177, 31902067752, 305441725601, 2924400160544, 27999196885618, 268073721835248, 2566628109851821, 24573761479828684, 235277465932911917, 2252625667246251996, 21567396521342873618

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

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 (8,22,-60,-67,60,22,-8,-1).

Formula

G.f.: (x^6 +4*x^5 -4*x^4 -16*x^3 +4*x^2 +4*x -1) / (-x^8 -8*x^7 +22*x^6 +60*x^5 -67*x^4 -60*x^3 +22*x^2 +8*x -1). - Alois P. Heinz, Dec 09 2013

Crossrefs

Sequence in context: A219566 A202790 A231833 * A232731 A215792 A388423

Adjacent sequences: A028452 A028453 A028454 * A028456 A028457 A028458

Keyword

nonn,easy

Author

Per H. Lundow

Status

approved