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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

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences:  A235088 A235089 A235090 * A235092 A235093 A235094

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 03 2014

STATUS

approved

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Last modified May 22 02:18 EDT 2022. Contains 353933 sequences. (Running on oeis4.)