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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. 1
67, 146, 439, 1187, 3227, 8964, 24719, 67952, 187266, 516133, 1421669, 3916441, 10790266, 29726787, 81895288, 225619582, 621575781, 1712418521, 4717655719, 12996990098, 35806276733, 98645103102, 271764008258, 748700872883 (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) + 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

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Last modified August 5 06:18 EDT 2021. Contains 346457 sequences. (Running on oeis4.)