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A251094 Number of (n+1) X (2+1) 0..1 arrays with no 2 X 2 subblock having its minimum diagonal element less than its minimum antidiagonal element. 1
41, 212, 1109, 5817, 30517, 160086, 839758, 4405079, 23107524, 121214121, 635847599, 3335437865, 17496560104, 91780937840, 481451239589, 2525527648328, 13248049600905, 69494712657097, 364545365754237, 1912279634115658 (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) = 7*a(n-1) - 11*a(n-2) + 10*a(n-3) - 3*a(n-4).

Empirical g.f.: x*(41 - 75*x + 76*x^2 - 24*x^3) / (1 - 7*x + 11*x^2 - 10*x^3 + 3*x^4). - Colin Barker, Nov 25 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A251100.

Sequence in context: A297598 A204620 A172085 * A300464 A326228 A142392

Adjacent sequences:  A251091 A251092 A251093 * A251095 A251096 A251097

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 29 2014

STATUS

approved

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Last modified October 18 17:13 EDT 2019. Contains 328186 sequences. (Running on oeis4.)