A205328 Number of (n+1) X 2 0..2 arrays with the number of equal 2 X 2 subblock diagonal pairs and equal antidiagonal pairs differing from each horizontal or vertical neighbor, and new values 0..2 introduced in row major order.

14, 72, 396, 2160, 11808, 64512, 352512, 1926144, 10524672, 57507840, 314228736, 1716977664, 9381740544, 51262783488, 280105058304, 1530522501120, 8362930470912, 45695901892608, 249687051337728, 1364315420491776

Offset

1,1

Comments

Column 1 of A205335.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 8*a(n-2) for n>3.

Empirical g.f.: 2*x*(7 + 8*x - 2*x^2) / (1 - 4*x - 8*x^2). - Colin Barker, Mar 03 2018

Example

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

Crossrefs

Cf. A205335.

Sequence in context: A212750 A106845 A365670 * A328735 A279447 A205590

Adjacent sequences: A205325 A205326 A205327 * A205329 A205330 A205331

Keyword

nonn

Author

R. H. Hardin, Jan 26 2012

Status

approved