A234667 - OEIS

A234667

Number of (n+1) X (1+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4 (constant-stress 1 X 1 tilings).

492, 3816, 29568, 229272, 1778412, 13801056, 107144508, 832197192, 6466444032, 50269824456, 390963554148, 3042084148512, 23680823914452, 184429911964056, 1437009243823488, 11202089753841432, 87364420495436172, 681684020356757856

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OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 14*a(n-1) + 25*a(n-2) - 950*a(n-3) + 2091*a(n-4) + 7326*a(n-5) - 3780*a(n-6) - 10080*a(n-7).

Empirical g.f.: 12*x*(41 - 256*x - 3013*x^2 + 15610*x^3 + 35486*x^4 - 26880*x^5 - 53760*x^6) / ((1 - 8*x)*(1 - 6*x - 12*x^2)*(1 - 61*x^2 + 105*x^4)). - Colin Barker, Oct 16 2018

EXAMPLE

Some solutions for n=3:

5 1 7 7 0 2 1 3 4 6 4 5 2 4 3 2 5 5 7 1

1 1 0 4 0 6 4 2 0 6 4 1 4 2 2 5 3 7 7 5

6 2 5 5 5 7 4 6 2 4 1 2 4 6 4 3 0 0 4 6

5 5 2 6 2 0 6 4 7 5 0 5 6 4 7 2 3 7 0 6

CROSSREFS

Column 1 of A234672.

Sequence in context: A226715 A205819 A234672 * A231455 A007242 A198531

Adjacent sequences: A234664 A234665 A234666 * A234668 A234669 A234670

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 29 2013

STATUS

approved