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A235273 Number of (n+1) X (3+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 5 (constant stress 1 X 1 tilings). 1
208, 380, 632, 1280, 2344, 5096, 10088, 23000, 48328, 113720, 249512, 599480, 1355464, 3301496, 7618088, 18722360, 43787848, 108247160, 255425192, 633863480, 1504419784, 3742789496, 8917090088, 22221233720, 53073853768, 132403182200 (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) = a(n-1) + 15*a(n-2) - 15*a(n-3) - 80*a(n-4) + 80*a(n-5) + 180*a(n-6) - 180*a(n-7) - 144*a(n-8) + 144*a(n-9).

Empirical g.f.: 4*x*(52 + 43*x - 717*x^2 - 483*x^3 + 3481*x^4 + 1698*x^5 - 7062*x^6 - 1872*x^7 + 5040*x^8) / ((1 - x)*(1 - 2*x)*(1 + 2*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Oct 18 2018

EXAMPLE

Some solutions for n=4:

..3..0..2..0....4..2..4..2....3..0..3..0....4..2..4..2....4..0..4..2

..1..3..0..3....0..3..0..3....0..2..0..2....1..4..1..4....1..2..1..4

..4..1..3..1....2..0..2..0....3..0..3..0....3..1..3..1....4..0..4..2

..1..3..0..3....1..4..1..4....0..2..0..2....0..3..0..3....0..1..0..3

..3..0..2..0....2..0..2..0....4..1..4..1....2..0..2..0....4..0..4..2

CROSSREFS

Column 3 of A235280.

Sequence in context: A283152 A260365 A131686 * A255082 A255075 A304281

Adjacent sequences:  A235270 A235271 A235272 * A235274 A235275 A235276

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2014

STATUS

approved

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Last modified May 25 15:53 EDT 2020. Contains 334593 sequences. (Running on oeis4.)