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A235312 Number of (n+1) X (1+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7 (constant-stress 1 X 1 tilings). 1
112, 392, 1120, 3920, 11776, 41216, 128128, 448448, 1426432, 4992512, 16130560, 56456960, 184446976, 645564416, 2126645248, 7443258368, 24679432192, 86378012672, 287911321600, 1007689625600, 3373484670976, 11807196348416 (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) = 28*a(n-2) -252*a(n-4) +720*a(n-6).

Empirical g.f.: 8*x*(2 + 7*x)*(7 - 126*x^2 + 540*x^4) / ((1 - 6*x^2)*(1 - 10*x^2)*(1 - 12*x^2)). - Colin Barker, Oct 18 2018

EXAMPLE

Some solutions for n=4:

  4 2   6 2   3 2   2 3   1 2   4 0   5 0   5 0   3 5   3 0

  0 5   0 3   0 6   6 0   6 0   1 4   0 2   2 4   6 1   1 5

  3 1   5 1   6 5   5 6   4 5   5 1   5 0   6 1   3 5   6 3

  1 6   0 3   0 6   6 0   6 0   0 3   3 5   3 5   6 1   2 6

  4 2   4 0   2 1   5 6   5 6   5 1   5 0   5 0   2 4   3 0

CROSSREFS

Column 1 of A235319.

Sequence in context: A233885 A235319 A203923 * A203916 A234681 A234674

Adjacent sequences:  A235309 A235310 A235311 * A235313 A235314 A235315

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2014

STATUS

approved

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Last modified August 13 11:30 EDT 2022. Contains 356091 sequences. (Running on oeis4.)