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A237560 Number of (n+1) X (1+1) 0..2 arrays with the upper median plus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one. 1
81, 316, 1256, 4984, 19900, 78144, 311512, 1227648, 4896848, 19273664, 76861056, 302658560, 1207072128, 4752337152, 18952790656, 74623190528, 297608324608, 1171752619008, 4673101527552, 18399231225856, 73378645568512 (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) = 4*a(n-2) + 140*a(n-4) + 632*a(n-6) + 864*a(n-8) for n>9.

Empirical g.f.: x*(81 + 316*x + 932*x^2 + 3720*x^3 + 3536*x^4 + 13968*x^5 + 4880*x^6 + 17600*x^7 + 1024*x^8) / (1 - 4*x^2 - 140*x^4 - 632*x^6 - 864*x^8). - Colin Barker, Oct 23 2018

EXAMPLE

Some solutions for n=5:

..1..0....2..0....2..0....0..1....0..2....2..0....0..2....0..1....0..1....2..0

..2..0....2..1....0..0....2..0....2..2....2..0....2..1....1..2....0..0....1..2

..2..0....1..0....2..1....2..0....0..1....2..1....2..2....0..0....2..1....0..1

..1..0....1..0....0..1....2..1....1..2....0..1....1..1....0..2....1..1....0..1

..1..2....2..1....2..2....2..2....0..0....2..0....0..1....1..0....0..0....1..2

..2..1....0..2....1..2....1..0....1..0....0..0....0..1....1..2....0..0....2..1

CROSSREFS

Column 1 of A237567.

Sequence in context: A237557 A237550 A237567 * A237332 A237325 A158776

Adjacent sequences: A237557 A237558 A237559 * A237561 A237562 A237563

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 09 2014

STATUS

approved

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Last modified February 8 23:03 EST 2023. Contains 360153 sequences. (Running on oeis4.)