A260132 Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 01010101 or 01010111.

58, 128, 342, 730, 1626, 3928, 8998, 20376, 47424, 109650, 251290, 579658, 1338500, 3080858, 7097716, 16367912, 37715574, 86898450, 200293226, 461601736, 1063705902, 2451421760, 5649587496, 13019565474, 30004282786, 69147284586

Offset

1,1

Links

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

Formula

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

Empirical g.f.: 2*x*(29 + 35*x + 78*x^2 - 15*x^3 - 72*x^4 - 46*x^5 + 5*x^6) / (1 - x - x^2 - 5*x^3 - x^4 + 3*x^5 + 3*x^6). - Colin Barker, Dec 28 2018

Example

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

Crossrefs

Column 2 of A260138.

Sequence in context: A044626 A039536 A348569 * A180571 A044309 A044690

Adjacent sequences: A260129 A260130 A260131 * A260133 A260134 A260135

Keyword

nonn

Author

R. H. Hardin, Jul 17 2015

Status

approved