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
KEYWORD
nonn
AUTHOR
STATUS
approved