A260241 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000101 or 00001001.

48, 99, 256, 635, 1598, 4027, 10110, 25421, 63884, 160475, 403392, 1013853, 2547460, 6402009, 16089526, 40433015, 101609368, 255352867, 641716970, 1612668111, 4052732014, 10184756245, 25594885072, 64321450263, 161643568800

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) - 2*a(n-2) + 9*a(n-3) - 4*a(n-4) + 9*a(n-5) - 9*a(n-6) for n>7.

Empirical g.f.: x*(48 + 3*x + 154*x^2 - 111*x^3 + 141*x^4 - 239*x^5 + 102*x^6) / (1 - 2*x + 2*x^2 - 9*x^3 + 4*x^4 - 9*x^5 + 9*x^6). - Colin Barker, Dec 28 2018

Example

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

Crossrefs

Column 1 of A260248.

Sequence in context: A070258 A260248 A260001 * A259994 A113797 A260294

Adjacent sequences: A260238 A260239 A260240 * A260242 A260243 A260244

Keyword

nonn

Author

R. H. Hardin, Jul 20 2015

Status

approved