A261704 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000101 or 00000111.

48, 76, 172, 338, 628, 1298, 2752, 5526, 10972, 22462, 46160, 93354, 188556, 384154, 782784, 1587790, 3221196, 6550678, 13318688, 27044962, 54927964, 111631314, 226840208, 460792838, 936118684, 1902095342, 3864635632, 7851378074

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) + a(n-3) + 5*a(n-4) - 3*a(n-5) - 5*a(n-6) + 3*a(n-7) - 4*a(n-8) + 2*a(n-9) for n>11.

Empirical g.f.: 2*x*(24 + 14*x + 24*x^2 + 21*x^3 - 99*x^4 - 38*x^5 + 48*x^6 - 45*x^7 + 47*x^8 - 6*x^9 - 2*x^10) / ((1 - x)*(1 - x^2 - 2*x^3 - 7*x^4 - 4*x^5 + x^6 - 2*x^7 + 2*x^8)). - Colin Barker, Dec 31 2018

Example

Some solutions for n=7:
..0..0..1....0..0..0....1..0..1....0..0..0....1..0..0....0..0..0....1..0..0
..0..0..0....0..1..0....0..0..0....0..1..0....1..1..0....1..0..0....0..0..0
..0..0..1....1..0..0....0..0..0....0..0..1....1..0..0....0..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....0..0..0....0..1..0....0..0..0....0..0..0....0..0..1....0..0..0
..0..1..0....0..0..1....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..0....0..0..0....0..1..1
..0..0..0....0..0..1....1..0..0....0..0..0....0..0..0....0..1..0....0..0..1
..0..0..0....0..1..0....0..1..0....0..1..0....0..0..1....0..1..0....0..0..0

Crossrefs

Column 1 of A261709.

Sequence in context: A328370 A143722 A261709 * A260370 A260363 A261553

Adjacent sequences: A261701 A261702 A261703 * A261705 A261706 A261707

Keyword

nonn

Author

R. H. Hardin, Aug 28 2015

Status

approved