A259887 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00000011.

34, 67, 215, 499, 936, 2212, 5352, 11529, 25397, 58793, 132494, 294066, 664222, 1503071, 3370883, 7574191, 17082212, 38445840, 86429444, 194563077, 438038913, 985523653, 2217627370, 4991511166, 11233246170, 25277953979, 56888391919

Offset

1,1

Links

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

Formula

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

Empirical g.f.: x*(34 + 33*x + 148*x^2 + 114*x^3) / (1 - x - 5*x^3 - 3*x^4). - Colin Barker, Dec 27 2018

Example

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

Crossrefs

Column 1 of A259894.

Sequence in context: A259962 A259894 A259955 * A028381 A277113 A036180

Adjacent sequences: A259884 A259885 A259886 * A259888 A259889 A259890

Keyword

nonn

Author

R. H. Hardin, Jul 07 2015

Status

approved