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A235091 Number of (n+1) X (1+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings). 1
80, 256, 808, 2580, 8184, 26164, 83224, 266572, 849688, 2726852, 8707160, 27993324, 89526552, 288291140, 923287256, 2977443116, 9547498136, 30828553348, 98964094552, 319913934828, 1027967064600, 3326345126596, 10697524464088 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 13*a(n-2) - 39*a(n-3) - 26*a(n-4) + 78*a(n-5).
Empirical g.f.: 4*x*(20 + 4*x - 250*x^2 - 13*x^3 + 501*x^4) / ((1 - 3*x)*(1 - 13*x^2 + 26*x^4)). - Colin Barker, Oct 17 2018
EXAMPLE
Some solutions for n=4:
0 3 4 2 3 2 5 2 5 2 1 2 0 1 4 1 2 5 2 5
1 0 2 4 5 0 3 4 3 4 4 1 5 2 3 4 4 3 5 4
0 3 4 2 2 1 4 1 0 5 3 4 2 3 4 1 2 5 0 3
1 0 2 4 5 0 1 2 2 3 0 5 0 5 1 2 4 3 2 1
2 5 3 1 2 1 3 0 5 2 3 4 1 2 4 1 2 5 0 3
CROSSREFS
Column 1 of A235098.
Sequence in context: A203355 A203348 A235098 * A306434 A234890 A157912
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2014
STATUS
approved

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Last modified April 16 22:53 EDT 2024. Contains 371755 sequences. (Running on oeis4.)