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A234260 Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant stress 1 X 1 tilings). 1
46, 88, 170, 358, 754, 1690, 3746, 8722, 19906, 47458, 110210, 266818, 626434, 1532290, 3623426, 8925442, 21208066, 52491778, 125134850, 310731778, 742387714, 1847564290, 4420706306, 11018178562, 26389889026, 65840439298, 157802201090 (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) = 3*a(n-1) + 6*a(n-2) - 24*a(n-3) + 4*a(n-4) + 36*a(n-5) - 24*a(n-6).

Empirical g.f.: 2*x*(23 - 25*x - 185*x^2 + 212*x^3 + 294*x^4 - 324*x^5) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 6*x^2)). - Colin Barker, Oct 14 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

CROSSREFS

Column 2 of A234266.

Sequence in context: A188598 A057454 A260278 * A211330 A121929 A007630

Adjacent sequences:  A234257 A234258 A234259 * A234261 A234262 A234263

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 22 2013

STATUS

approved

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Last modified September 21 13:37 EDT 2019. Contains 327253 sequences. (Running on oeis4.)