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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. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 20 14:44 EDT 2021. Contains 347586 sequences. (Running on oeis4.)