A261548 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000101 or 00001011.

48, 80, 170, 336, 652, 1293, 2588, 5100, 9996, 19788, 39102, 76977, 151492, 298988, 589456, 1160987, 2287512, 4509948, 8887914, 17512005, 34511260, 68019255, 134042352, 264143499, 520558296, 1025893511, 2021700618, 3984123909

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-2) + 2*a(n-3) + 6*a(n-4) - 8*a(n-6) - 2*a(n-7) - 5*a(n-8) - 2*a(n-9) + 5*a(n-10) + 2*a(n-12) for n>14.

Empirical g.f.: x*(48 + 80*x + 74*x^2 + 80*x^3 - 136*x^4 - 199*x^5 - 24*x^6 - 70*x^7 + 82*x^8 + 178*x^9 + 40*x^10 + 77*x^11 + 12*x^12 + 7*x^13) / (1 - 2*x^2 - 2*x^3 - 6*x^4 + 8*x^6 + 2*x^7 + 5*x^8 + 2*x^9 - 5*x^10 - 2*x^12). - Colin Barker, Dec 30 2018

Example

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

Crossrefs

Column 1 of A261553.

Sequence in context: A108608 A030628 A178739 * A065911 A260841 A260767

Adjacent sequences: A261545 A261546 A261547 * A261549 A261550 A261551

Keyword

nonn

Author

R. H. Hardin, Aug 24 2015

Status

approved