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A235292 Number of (n+1) X (2+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3 (constant stress 1 X 1 tilings). 1
108, 232, 476, 1132, 2556, 6532, 15692, 42100, 104988, 290932, 741836, 2101012, 5430876, 15615412, 40720652, 118353940, 310480668, 909550132, 2396120396, 7060652692, 18657656796, 55220768692, 146251030412, 434294562580 (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) + 17*a(n-2) - 57*a(n-3) - 86*a(n-4) + 372*a(n-5) + 76*a(n-6) - 972*a(n-7) + 360*a(n-8) + 864*a(n-9) - 576*a(n-10).

Empirical g.f.: 4*x*(27 - 23*x - 514*x^2 + 479*x^3 + 3395*x^4 - 3368*x^5 - 9102*x^6 + 9324*x^7 + 8352*x^8 - 8640*x^9) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 18 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

CROSSREFS

Column 2 of A235301.

Sequence in context: A044721 A095050 A275996 * A202202 A202195 A242867

Adjacent sequences:  A235289 A235290 A235291 * A235293 A235294 A235295

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2014

STATUS

approved

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Last modified September 20 01:31 EDT 2020. Contains 337243 sequences. (Running on oeis4.)