OFFSET
0,2
REFERENCES
Per Hakan Lundow, "Computation of matching polynomials and the number of 1-factors in polygraphs", Research reports, No 12, 1996, Department of Mathematics, Umea University.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..400
Per Hakan Lundow, Enumeration of matchings in polygraphs, 1998.
FORMULA
G.f.: -(x^28 -15*x^27 -284*x^26 +5183*x^25 +5371*x^24 -366892*x^23 +814436*x^22 +8226936*x^21 -29920872*x^20 -57862312*x^19 +331173012*x^18 -7873260*x^17 -1396434310*x^16 +1211992974*x^15 +1877432864*x^14 -2719474366*x^13 -471197866*x^12 +1952262300*x^11 -397859476*x^10 -507235480*x^9 +186066152*x^8 +41696904*x^7 -22010724*x^6 +36860*x^5 +598453*x^4 -36831*x^3 -2052*x^2 +159*x -1) / (x^30 -14*x^29 -430*x^28 +6634*x^27 +38158*x^26 -871958*x^25 +1251837*x^24 +29038240*x^23 -101668292*x^22 -290911416*x^21 +1623376452*x^20 +319719232*x^19 -9632041694*x^18 +7238239524*x^17 +21683751232*x^16 -26978306260*x^15 -17795407872*x^14 +34467592724*x^13 +1093570370*x^12 -17442114832*x^11 +3542012836*x^10 +3435559720*x^9 -1062456996*x^8 -223403632*x^7 +95033757*x^6 -1202342*x^5 -1914226*x^4 +150650*x^3 +338*x^2 -206*x +1). - Alois P. Heinz, Dec 09 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved