A037232 Number of matchings in graph C_{3} X C_{3} X P_{n}.

1, 370, 473888, 545223468, 633518934269, 735463713700160, 853881267896192137, 991358212180977707016, 1150970019455064994111456, 1336279754744865935702007958, 1551424939061435419705857645677, 1801209164368275134853509088988416

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..300

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

Formula

G.f.: -(x^24 +11*x^23 -4215*x^22 +37396*x^21 +704415*x^20 -2998831*x^19 -37542042*x^18 +36787261*x^17 +626732253*x^16 +13265126*x^15 -3881153331*x^14 -1042069103*x^13 +9636841166*x^12 +2382500981*x^11 -9372616945*x^10 -1901598356*x^9 +3355126577*x^8 +402988367*x^7 -393413958*x^6 -18907677*x^5 +11769531*x^4 +635050*x^3 -26013*x^2 -705*x +1) / (x^26 -15*x^25 -7121*x^24 +26330*x^23 +2687506*x^22 -4765556*x^21 -219906142*x^20 +162742094*x^19 +5311778728*x^18 -3223672790*x^17 -48803213494*x^16 +22293439868*x^15 +190488132168*x^14 -51256057908*x^13 -312306244606*x^12 +17426503078*x^11 +211285773166*x^10 +22492816500*x^9 -48774379794*x^8 -7508233118*x^7 +3205828392*x^6 +403354870*x^5 -40487210*x^4 -2637052*x^3 +102151*x^2 +1075*x -1). - Alois P. Heinz, Dec 09 2013

Crossrefs

Sequence in context: A283359 A254288 A281858 * A165330 A051182 A281860

Adjacent sequences: A037229 A037230 A037231 * A037233 A037234 A037235

Keyword

nonn

Author

Per H. Lundow

Status

approved