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A260241 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000101 or 00001001. 1
48, 99, 256, 635, 1598, 4027, 10110, 25421, 63884, 160475, 403392, 1013853, 2547460, 6402009, 16089526, 40433015, 101609368, 255352867, 641716970, 1612668111, 4052732014, 10184756245, 25594885072, 64321450263, 161643568800 (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-1) - 2*a(n-2) + 9*a(n-3) - 4*a(n-4) + 9*a(n-5) - 9*a(n-6) for n>7.

Empirical g.f.: x*(48 + 3*x + 154*x^2 - 111*x^3 + 141*x^4 - 239*x^5 + 102*x^6) / (1 - 2*x + 2*x^2 - 9*x^3 + 4*x^4 - 9*x^5 + 9*x^6). - Colin Barker, Dec 28 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A260248.

Sequence in context: A070258 A260248 A260001 * A259994 A113797 A260294

Adjacent sequences:  A260238 A260239 A260240 * A260242 A260243 A260244

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 20 2015

STATUS

approved

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Last modified October 19 11:40 EDT 2021. Contains 348088 sequences. (Running on oeis4.)