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

1,2

Comments

Column 3 of A301999.

Links

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

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

Example

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

Crossrefs

Cf. A301999, A049219.

Sequence in context: A149925 A149926 A321467 * A289589 A071739 A268407

Adjacent sequences: A301991 A301992 A301993 * A301995 A301996 A301997

Keyword

nonn

Author

R. H. Hardin, Mar 30 2018

Status

approved