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A251312 Number of (n+1) X (3+1) 0..1 arrays with no 2 X 2 subblock having the maximum of its diagonal elements greater than the absolute difference of its antidiagonal elements. 1
61, 238, 890, 3369, 12859, 48980, 186162, 707897, 2693783, 10250631, 38999597, 148376603, 564538287, 2147959151, 8172471594, 31094184171, 118305857859, 450125886029, 1712621797025, 6516115115442, 24792258076798, 94328620512132 (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) - 27*a(n-2) + 64*a(n-3) - 110*a(n-4) + 121*a(n-5) - 91*a(n-6) + 46*a(n-7) - 14*a(n-8) + a(n-9) - a(n-10).

Empirical g.f.: x*(61 - 250*x + 633*x^2 - 1229*x^3 + 1415*x^4 - 1090*x^5 + 552*x^6 - 163*x^7 - 2*x^8 - 11*x^9) / (1 - 8*x + 27*x^2 - 64*x^3 + 110*x^4 - 121*x^5 + 91*x^6 - 46*x^7 + 14*x^8 - x^9+ x^10). - Colin Barker, Nov 28 2018

EXAMPLE

Some solutions for n=4:

..1..1..1..0....1..1..1..1....0..0..0..1....1..1..1..0....0..1..1..0

..0..0..1..0....0..0..0..1....0..0..0..1....0..0..1..1....0..0..1..1

..0..0..1..1....1..0..0..1....1..0..0..0....1..0..0..0....0..0..0..1

..0..0..0..1....1..0..0..0....1..0..0..0....1..0..0..0....1..0..0..1

..1..1..0..1....1..1..1..0....1..0..0..0....1..1..1..0....1..0..0..1

CROSSREFS

Column 3 of A251317.

Sequence in context: A228130 A142267 A034863 * A158673 A174333 A158680

Adjacent sequences:  A251309 A251310 A251311 * A251313 A251314 A251315

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 01 2014

STATUS

approved

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Last modified October 17 17:21 EDT 2021. Contains 348065 sequences. (Running on oeis4.)