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A238039 Number of (n+1) X (1+1) 0..2 arrays with the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one. 1
81, 340, 1440, 6064, 25948, 109200, 466296, 1962720, 8385248, 35292928, 150759392, 634547840, 2710688576, 11409244416, 48737830912, 205137173504, 876305679104, 3688361604096, 15755932345856, 66316572940288, 283291082594304 (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) = 8*a(n-2) + 152*a(n-4) + 472*a(n-6) + 384*a(n-8).

Empirical g.f.: x*(81 + 340*x + 792*x^2 + 3344*x^3 + 2116*x^4 + 9008*x^5 + 1600*x^6 + 6912*x^7) / ((1 + 6*x^2)*(1 - 14*x^2 - 68*x^4 - 64*x^6)). - Colin Barker, Oct 24 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

CROSSREFS

Column 1 of A238046.

Sequence in context: A237965 A238046 A237958 * A232284 A337044 A337045

Adjacent sequences:  A238036 A238037 A238038 * A238040 A238041 A238042

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 17 2014

STATUS

approved

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Last modified May 28 13:05 EDT 2022. Contains 354115 sequences. (Running on oeis4.)