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A251124 Number of (n+1) X (4+1) 0..1 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the maximum of its antidiagonal elements. 1
72, 117, 173, 266, 401, 612, 938, 1452, 2266, 3565, 5646, 8991, 14379, 23071, 37107, 59788, 96455, 155750, 251656, 406798, 657784, 1063847, 1720828, 2783801, 4503681, 7286457, 11789033, 19074302, 30862061, 49935000, 80795606, 130729056 (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) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5) for n>6.

Empirical g.f.: x*(72 - 171*x + 65*x^2 + 87*x^3 - 59*x^4 + 3*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Nov 26 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 4 of A251128.

Sequence in context: A114128 A143610 A166987 * A169644 A078667 A090784

Adjacent sequences:  A251121 A251122 A251123 * A251125 A251126 A251127

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 30 2014

STATUS

approved

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Last modified September 21 19:57 EDT 2020. Contains 337273 sequences. (Running on oeis4.)