A260200 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00010001.

26, 44, 106, 220, 478, 1044, 2274, 4940, 10758, 23412, 50946, 110876, 241302, 525140, 1142866, 2487228, 5412966, 11780276, 25637506, 55795100, 121427318, 264263252, 575118258, 1251634556, 2723942534, 5928138484, 12901456482, 28077545820

Offset

1,1

Links

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

Formula

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

Empirical g.f.: 2*x*(13 - 4*x - 4*x^2 - 18*x^3 - 8*x^4 + 4*x^5 + 4*x^6) / (1 - 2*x - x^2 + 2*x^4 + 2*x^5). - Colin Barker, Dec 28 2018

Example

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

Crossrefs

Column 1 of A260207.

Sequence in context: A260207 A130771 A217775 * A178100 A357569 A255988

Adjacent sequences: A260197 A260198 A260199 * A260201 A260202 A260203

Keyword

nonn

Author

R. H. Hardin, Jul 19 2015

Status

approved