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.

81, 340, 1440, 6064, 25948, 109200, 466296, 1962720, 8385248, 35292928, 150759392, 634547840, 2710688576, 11409244416, 48737830912, 205137173504, 876305679104, 3688361604096, 15755932345856, 66316572940288, 283291082594304

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