A257442 Number of (n+2) X (3+2) 0..1 arrays with no 3 x 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 1 and no column sum 1.

39, 41, 47, 59, 77, 104, 143, 200, 284, 407, 587, 851, 1238, 1805, 2636, 3854, 5639, 8255, 12089, 17708, 25943, 38012, 55700, 81623, 119615, 175295, 256898, 376493, 551768, 808646, 1185119, 1736867, 2545493, 3730592, 5467439, 8012912, 11743484

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-3) - a(n-4) for n>6.

Empirical g.f.: x*(39 - 37*x + 4*x^2 - 33*x^3 + 4*x^4 + 3*x^5) / ((1 - x)*(1 - x - x^3)). - Colin Barker, Dec 21 2018

Example

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

Crossrefs

Column 3 of A257447.

Sequence in context: A223745 A050774 A041759 * A261374 A309696 A061756

Adjacent sequences: A257439 A257440 A257441 * A257443 A257444 A257445

Keyword

nonn

Author

R. H. Hardin, Apr 23 2015

Status

approved