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A251222
Number of (n+1) X (2+1) 0..1 arrays with no 2 X 2 subblock having the minimum of its diagonal elements greater than the absolute difference of its antidiagonal elements.
1
49, 305, 1892, 11753, 72985, 453273, 2814985, 17482154, 108570830, 674266427, 4187452312, 26005680486, 161505221644, 1003009195172, 6229070707553, 38684911434209, 240248095245952, 1492032555580773, 9266092805568853
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 9*a(n-2) - 8*a(n-3) - 8*a(n-4) + 3*a(n-5).
Empirical g.f.: x*(49 + 60*x - 74*x^2 - 60*x^3 + 24*x^4) / ((1 - x)*(1 + x)*(1 - 5*x - 8*x^2 + 3*x^3)). - Colin Barker, Nov 27 2018
EXAMPLE
Some solutions for n=4:
..0..1..1....0..1..1....1..1..0....1..0..1....0..0..0....1..1..1....0..1..1
..0..0..1....0..1..0....0..0..0....0..0..0....0..0..1....0..0..0....1..0..1
..0..0..0....0..1..1....0..0..0....1..1..1....0..1..1....1..0..1....1..1..0
..0..0..1....1..0..0....0..0..0....0..1..0....0..0..0....0..0..0....0..0..0
..0..0..0....0..0..1....1..1..1....1..1..1....0..0..0....1..0..1....0..0..0
CROSSREFS
Column 2 of A251228.
Sequence in context: A017354 A239607 A227079 * A250967 A245033 A340124
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 30 2014
STATUS
approved