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A234816
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 (constant-stress 1 X 1 tilings).
1
168, 686, 2380, 9716, 34092, 139112, 493348, 2011808, 7205628, 29360336, 106119940, 432009296, 1574462652, 6403264112, 23513001988, 95527797008, 353173605948, 1433355470576, 5331803584900, 21616468994576, 80854559348412
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) + 41*a(n-2) - 164*a(n-3) - 558*a(n-4) + 2232*a(n-5) + 2520*a(n-6) - 10080*a(n-7).
Empirical g.f.: 2*x*(84 + 7*x - 3626*x^2 - 189*x^3 + 51948*x^4 + 1260*x^5 - 246960*x^6) / ((1 - 4*x)*(1 - 12*x^2)*(1 - 14*x^2)*(1 - 15*x^2)). - Colin Barker, Oct 16 2018
EXAMPLE
Some solutions for n=5:
6 2 0 4 5 3 2 0 0 6 4 1 2 3 3 3 6 0 3 1
0 2 2 0 1 5 2 6 6 6 0 3 6 1 6 0 2 2 0 4
6 2 0 4 2 0 6 4 0 6 6 3 0 1 3 3 6 0 3 1
4 6 3 1 0 4 2 6 1 1 3 6 5 0 6 0 4 4 0 4
4 0 2 6 2 0 2 0 6 0 4 1 4 5 4 4 6 0 6 4
0 2 2 0 2 6 2 6 0 0 3 6 6 1 6 0 2 2 1 5
CROSSREFS
Column 1 of A234823.
Sequence in context: A234731 A157998 A234823 * A245868 A251461 A110285
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 31 2013
STATUS
approved