A259292 Number of (n+1) X (3+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0001 0101 or 0111.

66, 322, 1460, 6870, 31774, 148296, 688966, 3208946, 14925572, 69477150, 323263318, 1504482808, 7000820878, 32580094938, 151610945124, 705543988390, 3283282733102, 15279114925736, 71102455854262, 330882014413154

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 18*a(n-2) - 13*a(n-3) - 70*a(n-4) + 24*a(n-5) + 64*a(n-6).

Empirical g.f.: 2*x*(33 + 95*x - 186*x^2 - 494*x^3 + 280*x^4 + 512*x^5) / ((1 + 2*x)*(1 - 4*x - 10*x^2 + 33*x^3 + 4*x^4 - 32*x^5)). - Colin Barker, Dec 25 2018

Example

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

Crossrefs

Column 3 of A259297.

Sequence in context: A271739 A251055 A251048 * A258958 A120102 A244286

Adjacent sequences: A259289 A259290 A259291 * A259293 A259294 A259295

Keyword

nonn

Author

R. H. Hardin, Jun 23 2015

Status

approved