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A259245 Number of (n+1) X (3+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0011 or 0111. 1
48, 192, 720, 2816, 10720, 41552, 159168, 614560, 2360464, 9098240, 34986848, 134750672, 518448960, 1996103456, 7681731600, 29571245952, 113812664288, 438098128720, 1686212575424, 6490526009760, 24982143580048, 96159317085952 (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) + 12*a(n-2) - 11*a(n-3) - 30*a(n-4).

Empirical g.f.: 16*x*(3 + 6*x - 15*x^2 - 25*x^3) / (1 - 2*x - 12*x^2 + 11*x^3 + 30*x^4). - Colin Barker, Dec 24 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 3 of A259250.

Sequence in context: A210250 A259038 A231174 * A157923 A296367 A275507

Adjacent sequences:  A259242 A259243 A259244 * A259246 A259247 A259248

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 22 2015

STATUS

approved

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Last modified October 20 21:29 EDT 2021. Contains 348119 sequences. (Running on oeis4.)