A260494 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001011.

48, 83, 218, 464, 722, 1600, 3446, 6277, 12596, 26271, 51082, 100763, 204716, 406841, 804806, 1614143, 3223294, 6404160, 12784652, 25529935, 50847034, 101384899, 202319592, 403339059, 804133704, 1603982398, 3198547326, 6377529472

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-3) + 4*a(n-4) + 4*a(n-5) + 4*a(n-6) + 4*a(n-7) + 3*a(n-8) + 2*a(n-9) + 3*a(n-10) + 2*a(n-11) + a(n-12) for n>14.

Empirical g.f.: x*(48 + 83*x + 218*x^2 + 272*x^3 + 198*x^4 + 204*x^5 + 194*x^6 + 137*x^7 + 104*x^8 + 126*x^9 + 82*x^10 + 26*x^11 - 6*x^12 - 2*x^13) / (1 - 4*x^3 - 4*x^4 - 4*x^5 - 4*x^6 - 4*x^7 - 3*x^8 - 2*x^9 - 3*x^10 - 2*x^11 - x^12). - Colin Barker, Dec 29 2018

Example

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

Crossrefs

Column 1 of A260501.

Sequence in context: A260834 A260760 A260501 * A039426 A043249 A044029

Adjacent sequences: A260491 A260492 A260493 * A260495 A260496 A260497

Keyword

nonn

Author

R. H. Hardin, Jul 27 2015

Status

approved