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A185459 Number of (n+1) X 2 binary arrays with no 2 X 2 subblock determinant equal to any horizontal or vertical neighbor 2 X 2 subblock determinant. 1
16, 34, 92, 218, 540, 1320, 3238, 7934, 19450, 47672, 116850, 286412, 702028, 1720746, 4217738, 10338138, 25339908, 62110890, 152240596, 373158376, 914652054, 2241912374, 5495172802, 13469270464, 33014657298, 80922541380 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A185467.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = a(n-1) + 2*a(n-2) + 3*a(n-3) + 2*a(n-4) for n>5.

Empirical g.f.: 2*x*(8 + 9*x + 13*x^2 + 5*x^3 + 2*x^4) / (1 - x - 2*x^2 - 3*x^3 - 2*x^4). - Colin Barker, Apr 15 2018

EXAMPLE

Some solutions for 3 X 2:

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

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

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

CROSSREFS

Cf. A185467.

Sequence in context: A209377 A203446 A153819 * A279712 A228800 A230943

Adjacent sequences:  A185456 A185457 A185458 * A185460 A185461 A185462

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 28 2011

STATUS

approved

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Last modified October 17 17:21 EDT 2021. Contains 348065 sequences. (Running on oeis4.)