A221122 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor.

21, 1950, 179300, 16436223, 1506094707, 138001217828, 12644783009532, 1158616222843158, 106161685080363377, 9727382617196220288, 891300589691816054472, 81668088157651470747218, 7483083373227566657384892

Offset: 1

Author

R. H. Hardin, Jan 02 2013

Keywords

• nonn

Comments

Column 4 of A221125.

Examples

			Some solutions for n=3:
  1 1 1 0     0 3 1 1     0 2 0 2     1 1 0 1     1 0 2 0
  1 2 1 1     1 1 1 2     1 3 0 1     0 1 3 0     0 3 4 0
  0 1 3 0     0 1 0 1     0 0 1 2     0 3 1 1     0 1 1 0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..18

Crossrefs

Cf. A221125.

Formula

Empirical: a(n) = 109*a(n-1) - 1680*a(n-2) + 8230*a(n-3) - 13300*a(n-4) + 2025*a(n-5) for n>6.

Empirical g.f.: x*(21 - 339*x + 2030*x^2 - 4307*x^3 + 1200*x^4 + 2880*x^5) / (1 - 109*x + 1680*x^2 - 8230*x^3 + 13300*x^4 - 2025*x^5). - Colin Barker, Aug 03 2018