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A235291
Number of (n+1) X (1+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
40, 108, 272, 744, 1888, 5232, 13376, 37536, 96640, 274368, 710912, 2039424, 5314048, 15382272, 40272896, 117459456, 308746240, 906083328, 2389348352, 7047112704, 18631057408, 55167578112, 146146082816, 434084683776
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 14*a(n-2) - 48*a(n-4).
Empirical g.f.: 4*x*(10 + 27*x - 72*x^2 - 192*x^3) / ((1 - 6*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 18 2018
EXAMPLE
Some solutions for n=5:
3 0 2 2 3 0 1 3 1 1 3 0 0 1 3 3 1 0 1 3
1 1 3 0 1 1 2 1 0 3 2 2 3 1 0 3 0 2 3 2
3 0 1 1 3 0 0 2 1 1 3 0 0 1 1 1 1 0 0 2
0 0 3 0 2 2 2 1 0 3 2 2 3 1 3 0 0 2 1 0
0 3 1 1 3 0 1 3 3 3 3 0 0 1 3 3 1 0 1 3
1 1 3 0 1 1 1 0 3 0 2 2 3 1 0 3 1 3 1 0
CROSSREFS
Column 1 of A235301.
Sequence in context: A241024 A123992 A235301 * A235893 A192791 A345970
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2014
STATUS
approved