A301994 Number of n X 3 0..1 arrays with every element equal to 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.

1, 2, 5, 15, 48, 155, 499, 1602, 5137, 16467, 52784, 169199, 542375, 1738618, 5573261, 17865479, 57269040, 183579891, 588478091, 1886407378, 6047009817, 19384109803, 62137109808, 199184819687, 638500768991, 2046758546378, 6561026627701

Offset: 1

Author

R. H. Hardin, Mar 30 2018

Keywords

• nonn

Comments

Column 3 of A301999.

Examples

			Some solutions for n=5:
  0 0 0   0 0 1   0 0 1   0 0 1   0 0 1   0 0 0   0 0 1
  1 1 0   1 1 0   1 1 1   0 1 1   1 1 1   1 1 0   1 1 1
  1 0 0   0 0 0   1 0 0   0 0 1   1 1 1   0 0 0   1 0 0
  1 1 0   0 1 1   1 1 0   0 1 0   1 0 0   0 1 0   1 1 1
  1 0 0   1 0 0   1 0 0   1 0 0   0 1 1   1 0 0   0 0 0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A301999, A049219.

Formula

Empirical: a(n) = 5*a(n-1) - 7*a(n-2) + 4*a(n-3).

Empirical: partial sums of A049219. - Sean A. Irvine, Jul 13 2022