A251127 Number of (n+1) X (7+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.

354, 510, 680, 938, 1268, 1743, 2420, 3429, 4957, 7321, 11025, 16890, 26241, 41224, 65310, 104116, 166730, 267857, 431290, 695527, 1122859, 1814075, 2932255, 4741268, 7668063, 12403458, 20065220, 32461934, 52519952, 84974211, 137486000

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*(354 - 906*x + 410*x^2 + 414*x^3 - 302*x^4 + 15*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Nov 26 2018

Example

Some solutions for n=4:
..0..0..0..0..0..0..0..1....0..0..0..1..0..1..0..1....0..0..0..0..0..0..1..0
..0..0..0..0..0..0..0..1....0..0..0..1..0..1..0..0....0..0..0..0..0..0..1..0
..0..0..0..0..0..0..0..1....0..0..0..1..0..1..0..0....0..0..0..0..0..0..1..0
..1..1..1..1..1..1..1..1....0..0..0..1..0..1..0..0....0..0..0..0..0..0..1..0
..1..0..0..0..0..0..0..0....0..0..0..1..0..1..0..0....1..1..1..1..1..1..1..0

Crossrefs

Column 7 of A251128.

Sequence in context: A068684 A377219 A270782 * A176197 A157668 A374696

Adjacent sequences: A251124 A251125 A251126 * A251128 A251129 A251130

Keyword

nonn

Author

R. H. Hardin, Nov 30 2014

Status

approved