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A234651 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 (constant stress 1 X 1 tilings). 1
160, 728, 3264, 15008, 67840, 315008, 1434624, 6722048, 30822400, 145614848, 671760384, 3197247488, 14829813760, 71052197888, 331140562944, 1595912880128, 7469054033920, 36183831216128, 169965785186304, 827149902675968 (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) = 4*a(n-1) + 44*a(n-2) - 176*a(n-3) - 480*a(n-4) + 1920*a(n-5).

Empirical g.f.: 8*x*(20 + 11*x - 836*x^2 - 240*x^3 + 8640*x^4) / ((1 - 4*x)*(1 - 20*x^2)*(1 - 24*x^2)). - Colin Barker, Oct 15 2018

EXAMPLE

Some solutions for n=5:

..5..2....4..4....2..4....5..1....0..1....1..2....2..3....5..4....2..2....1..4

..4..5....4..0....3..1....1..1....5..2....4..1....4..1....0..3....1..5....2..1

..5..2....5..5....2..4....4..0....1..2....1..2....2..3....1..0....2..2....1..4

..0..1....0..4....4..2....1..1....5..2....3..0....4..1....2..5....0..4....5..4

..5..2....1..1....0..2....4..0....0..1....3..4....1..2....5..4....5..5....0..3

..1..2....1..5....2..0....4..4....0..5....0..5....3..0....5..0....0..4....4..3

CROSSREFS

Column 1 of A234658.

Sequence in context: A233917 A233910 A234658 * A234898 A234891 A305272

Adjacent sequences:  A234648 A234649 A234650 * A234652 A234653 A234654

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 29 2013

STATUS

approved

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Last modified February 28 09:24 EST 2021. Contains 341695 sequences. (Running on oeis4.)