A259956 Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00001001.

67, 146, 439, 1187, 3227, 8964, 24719, 67952, 187266, 516133, 1421669, 3916441, 10790266, 29726787, 81895288, 225619582, 621575781, 1712418521, 4717655719, 12996990098, 35806276733, 98645103102, 271764008258, 748700872883

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 2*a(n-2) + 6*a(n-3) + 5*a(n-4) + a(n-5) - 2*a(n-6) - 2*a(n-7) - a(n-8) for n>9.

Empirical g.f.: x*(67 + 79*x + 159*x^2 + 54*x^3 - 49*x^4 - 68*x^5 - 28*x^6 - 5*x^7 + 7*x^8) / (1 - x - 2*x^2 - 6*x^3 - 5*x^4 - x^5 + 2*x^6 + 2*x^7 + x^8). - Colin Barker, Dec 27 2018

Example

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

Crossrefs

Column 2 of A259962.

Sequence in context: A238083 A118200 A163303 * A044318 A044699 A142223

Adjacent sequences: A259953 A259954 A259955 * A259957 A259958 A259959

Keyword

nonn

Author

R. H. Hardin, Jul 10 2015

Status

approved