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A205188 Number of (n+1) X 4 0..1 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor. 1
48, 64, 124, 160, 292, 384, 708, 928, 1708, 2240, 4124, 5408, 9956, 13056, 24036, 31520, 58028, 76096, 140092, 183712, 338212, 443520, 816516, 1070752, 1971244, 2585024, 4759004, 6240800, 11489252, 15066624, 27737508, 36374048, 66964268 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A205193.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

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

Empirical g.f.: 4*x*(12 + 16*x + 7*x^2 + 8*x^3 - x^4) / (1 - 2*x^2 - x^4). - Colin Barker, Jun 11 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A205193.

Sequence in context: A114505 A323610 A186400 * A333672 A045072 A217139

Adjacent sequences:  A205185 A205186 A205187 * A205189 A205190 A205191

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 23 2012

STATUS

approved

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Last modified September 18 01:54 EDT 2021. Contains 347504 sequences. (Running on oeis4.)