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A251243 Number of (n+1) X (2+1) 0..2 arrays with no 2 X 2 subblock having the sum of its diagonal elements less than the minimum of its antidiagonal elements. 1
621, 14265, 327753, 7530633, 173028393, 3975606801, 91345992921, 2098821870081, 48223825786089, 1108020364732593, 25458559305394041, 584951560945849089, 13440207851070791625, 308810505245808515409, 7095420636859874120985 (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) = 27*a(n-1) - 94*a(n-2) + 36*a(n-3) - 4*a(n-4) - 36*a(n-5).

Empirical g.f.: 9*x*(69 - 278*x + 108*x^2 - 16*x^3 - 108*x^4) / (1 - 27*x + 94*x^2 - 36*x^3 + 4*x^4 + 36*x^5). - Colin Barker, Nov 27 2018

EXAMPLE

Some solutions for n=2:

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

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

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

CROSSREFS

Column 2 of A251249.

Sequence in context: A232422 A189119 A203086 * A184226 A260764 A224432

Adjacent sequences:  A251240 A251241 A251242 * A251244 A251245 A251246

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 01 2014

STATUS

approved

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Last modified December 14 05:36 EST 2019. Contains 329978 sequences. (Running on oeis4.)