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A251049 Number of (n+1) X (2+1) 0..3 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the absolute difference of its antidiagonal elements. 1
290, 1528, 4334, 11280, 25847, 56676, 118925, 247753, 515324, 1087674, 2331944, 5093511, 11294058, 25360220, 57445566, 130937588, 299629648, 687412847, 1579482633, 3632619857, 8359090437, 19241386917, 44298667688, 101997419499 (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) = 8*a(n-1) - 25*a(n-2) + 35*a(n-3) - 7*a(n-4) - 49*a(n-5) + 77*a(n-6) - 55*a(n-7) + 20*a(n-8) - 3*a(n-9) for n>11.

Empirical g.f.: x*(290 - 792*x - 640*x^2 + 4658*x^3 - 7493*x^4 + 5116*x^5 - 228*x^6 - 1772*x^7 + 936*x^8 - 113*x^9 - 19*x^10) / ((1 - x)^7*(1 - x - 3*x^2)). - Colin Barker, Nov 24 2018

EXAMPLE

Some solutions for n=4:

..0..1..2....1..0..3....1..0..3....0..0..2....2..3..3....1..3..3....0..0..2

..0..0..0....1..0..3....1..0..3....0..0..0....0..0..0....0..0..0....0..0..2

..3..3..3....1..0..1....1..0..3....0..0..0....0..0..0....3..3..3....0..0..1

..0..0..0....1..0..0....2..0..1....1..0..0....1..0..0....0..0..0....0..0..0

..0..0..0....2..1..1....3..0..1....2..0..0....3..2..1....3..3..1....3..3..3

CROSSREFS

Column 2 of A251055.

Sequence in context: A295483 A075299 A031712 * A108881 A186547 A237741

Adjacent sequences:  A251046 A251047 A251048 * A251050 A251051 A251052

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 29 2014

STATUS

approved

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Last modified October 28 04:43 EDT 2021. Contains 348313 sequences. (Running on oeis4.)