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A234262
Number of (n+1) X (4+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
244, 358, 560, 988, 1816, 3616, 7304, 15544, 33064, 73288, 161000, 367528, 826216, 1930216, 4416104, 10507624, 24366184, 58801768, 137742440, 335934568, 792768616, 1948301416, 4622131304, 11420979304, 27195392104, 67451347048
OFFSET
1,1
LINKS
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*(122 - 187*x - 989*x^2 + 1508*x^3 + 1554*x^4 - 2268*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 0 0 0 0 0 0 0 0 0 2 0 2 0 2 2 1 0 0
2 0 0 2 0 2 0 2 0 2 0 0 0 0 0 2 0 1 2 0
2 2 0 0 0 0 0 0 0 0 0 2 0 2 0 2 2 1 0 0
2 0 0 2 0 2 0 2 0 2 1 1 1 1 1 2 0 1 2 0
2 2 0 0 0 2 2 2 2 2 2 0 2 0 2 2 2 1 0 0
2 0 0 2 0 2 0 2 0 2 2 2 2 2 2 2 0 1 2 0
CROSSREFS
Column 4 of A234266.
Sequence in context: A051002 A044987 A201998 * A031786 A328206 A135409
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2013
STATUS
approved