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A028455
Number of perfect matchings in graph P_{2} X C_{3} X P_{n}.
1
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
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.
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 A280358
KEYWORD
nonn
AUTHOR
STATUS
approved