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A259766 Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 or 00000101. 1
49, 87, 167, 299, 564, 1086, 2045, 3870, 7371, 14001, 26647, 50766, 96574, 183815, 350088, 666497, 1268925, 2416285, 4600654, 8759750, 16679685, 31759384, 60472021, 115144725, 219245665, 417461876, 794885812, 1513533557, 2881900030 (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) = a(n-1) + a(n-2) + a(n-3) + 2*a(n-4) - 2*a(n-5) + 2*a(n-6) - 4*a(n-7) - 3*a(n-8) + 2*a(n-9) - 4*a(n-10) + 2*a(n-11) for n>12.

Empirical g.f.: x*(49 + 38*x + 31*x^2 - 4*x^3 - 87*x^4 - 20*x^5 - 162*x^6 - 67*x^7 + x^8 - 96*x^9 + 78*x^10 - 6*x^11) / (1 - x - x^2 - x^3 - 2*x^4 + 2*x^5 - 2*x^6 + 4*x^7 + 3*x^8 - 2*x^9 + 4*x^10 - 2*x^11). - Colin Barker, Dec 27 2018

EXAMPLE

Some solutions for n=4:

..0..0..0..0....0..0..1..0....0..0..0..1....0..1..0..0....0..0..0..1

..0..1..0..0....0..0..0..1....1..0..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....1..0..0..1

..0..0..0..0....1..0..0..0....1..0..0..1....0..0..0..1....0..0..0..0

..1..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....1..0..1..0

CROSSREFS

Column 2 of A259770.

Sequence in context: A250074 A247678 A093894 * A273937 A326257 A231275

Adjacent sequences:  A259763 A259764 A259765 * A259767 A259768 A259769

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 04 2015

STATUS

approved

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Last modified May 6 09:22 EDT 2021. Contains 343580 sequences. (Running on oeis4.)