A261260 Number of (n+2) X (3+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 00100101 or 01010101.

91, 110, 288, 690, 1483, 2948, 6795, 14292, 32297, 66828, 151277, 315528, 713289, 1485412, 3353269, 6999606, 15784789, 32971814, 74265077, 155329758, 349486647, 731717900, 1644547773, 3446906988, 7738976061, 16237071190, 36418432025

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-2) + 10*a(n-4) + a(n-5) + 9*a(n-6) + a(n-7) + 6*a(n-8) + 2*a(n-10) - 4*a(n-11) + 4*a(n-12) for n>13.

Empirical g.f.: x*(91 + 110*x + 106*x^2 + 470*x^3 - 3*x^4 + 377*x^5 + 20*x^6 + 127*x^7 - 61*x^8 + 123*x^9 - 162*x^10 + 146*x^11 - 28*x^12) / (1 - 2*x^2 - 10*x^4 - x^5 - 9*x^6 - x^7 - 6*x^8 - 2*x^10 + 4*x^11 - 4*x^12). - Colin Barker, Dec 30 2018

Example

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

Crossrefs

Column 3 of A261265.

Sequence in context: A184034 A294742 A224981 * A161945 A140389 A236845

Adjacent sequences: A261257 A261258 A261259 * A261261 A261262 A261263

Keyword

nonn

Author

R. H. Hardin, Aug 13 2015

Status

approved