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A235232
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 6, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).
1
120, 420, 1328, 4652, 14944, 52468, 170864, 601100, 1980544, 6979348, 23223440, 81953324, 274931488, 971325748, 3280518320, 11600884556, 39397352128, 139427487316, 475663660496, 1684432450412, 5768254899040, 20437259824756
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 23*a(n-2) - 63*a(n-3) - 153*a(n-4) + 333*a(n-5) + 249*a(n-6) - 81*a(n-7) - 54*a(n-8).
Empirical g.f.: 4*x*(30 + 15*x - 673*x^2 - 358*x^3 + 3816*x^4 + 2151*x^5 - 933*x^6 - 528*x^7) / ((1 - 3*x)*(1 + 3*x)*(1 - 3*x - 2*x^2)*(1 - 12*x^2 + 3*x^4)). - Colin Barker, Oct 17 2018
EXAMPLE
Some solutions for n=4:
2 0 2 1 2 4 3 0 1 3 4 1 3 6 4 1 5 0 2 5
1 5 0 5 6 2 2 5 4 0 0 3 5 2 3 6 4 5 4 1
3 1 1 0 3 5 6 3 1 3 3 0 0 3 5 2 6 1 0 3
0 4 0 5 5 1 3 6 4 0 1 4 4 1 2 5 2 3 3 0
2 0 3 2 4 6 4 1 0 2 5 2 3 6 5 2 5 0 1 4
CROSSREFS
Column 1 of A235239.
Sequence in context: A307933 A235239 A337469 * A304284 A167562 A033697
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2014
STATUS
approved