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.

61, 238, 890, 3369, 12859, 48980, 186162, 707897, 2693783, 10250631, 38999597, 148376603, 564538287, 2147959151, 8172471594, 31094184171, 118305857859, 450125886029, 1712621797025, 6516115115442, 24792258076798, 94328620512132

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