A260364 Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001111.

78, 127, 342, 700, 896, 2047, 4438, 6674, 12878, 27877, 46806, 84404, 175894, 316729, 562556, 1122802, 2100112, 3759241, 7255522, 13784466, 25036860, 47321615, 90142076, 165956528, 310385576, 589328265, 1095576864, 2041368188, 3857505346

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-2) + 5*a(n-3) + 5*a(n-4) - 4*a(n-5) - 6*a(n-6) - 10*a(n-7) - 7*a(n-8) + 4*a(n-9) + 5*a(n-10) + 5*a(n-11) + 3*a(n-12).

Empirical g.f.: x*(78 + 127*x + 264*x^2 + 183*x^3 - 471*x^4 - 686*x^5 - 692*x^6 - 443*x^7 + 393*x^8 + 559*x^9 + 428*x^10 + 268*x^11) / ((1 - x)*(1 + x)^2*(1 + x^2)*(1 - x - 5*x^3 + x^4 + 3*x^5 + 2*x^6 + 3*x^7)). - Colin Barker, Dec 29 2018

Example

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

Crossrefs

Column 2 of A260370.

Sequence in context: A224666 A161596 A275218 * A185077 A042945 A044329

Adjacent sequences: A260361 A260362 A260363 * A260365 A260366 A260367

Keyword

nonn

Author

R. H. Hardin, Jul 23 2015

Status

approved