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A251106 Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having the maximum of its diagonal elements greater than the absolute difference of its antidiagonal elements. 1
37, 147, 526, 1844, 6544, 23334, 83126, 295938, 1053609, 3751373, 13356805, 47556710, 169324797, 602878211, 2146538499, 7642716637, 27211772110, 96887085837, 344964943222, 1228242247433, 4373137177399, 15570486043677 (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) = 5*a(n-1) - 8*a(n-2) + 13*a(n-3) - 12*a(n-4) + 9*a(n-5) - 5*a(n-6) + a(n-7).

Empirical g.f.: x*(37 - 38*x + 87*x^2 - 91*x^3 + 65*x^4 - 41*x^5 + 10*x^6) / ((1 + x^2)*(1 - 5*x + 7*x^2 - 8*x^3 + 5*x^4 - x^5)). - Colin Barker, Nov 25 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 1 of A251113.

Sequence in context: A031690 A157324 A251113 * A141968 A142656 A145898

Adjacent sequences:  A251103 A251104 A251105 * A251107 A251108 A251109

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 30 2014

STATUS

approved

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Last modified May 17 02:39 EDT 2022. Contains 353727 sequences. (Running on oeis4.)