A288031 Number of edge covers in the grid graph P_3 X P_n.

1, 43, 969, 23663, 571099, 13807469, 333735575, 8066926825, 194989463233, 4713185791699, 113924706164937, 2753729539353359, 66561737202707371, 1608896152717277333, 38889412128248718215, 940014912175876488361, 22721558047666401897553, 549213840574693856578267

Offset: 1

Author

Andrew Howroyd, Jun 04 2017

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..200

Crossrefs

Row 3 of A286912.

Cf. A286911, A286913.

Formula

Empirical: a(n) = 20*a(n-1)+100*a(n-2)+24*a(n-3) -95*a(n-4)+10*a(n-5)+8*a(n-6) for n>6.

Empirical g.f.: x*(1 + 23*x + 9*x^2 - 41*x^3 + 2*x^4 + 8*x^5) / (1 - 20*x - 100*x^2 - 24*x^3 + 95*x^4 - 10*x^5 - 8*x^6). - Colin Barker, Jun 11 2017