A257441 Number of (n+2) X (2+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.

36, 38, 41, 51, 68, 95, 134, 191, 275, 398, 578, 842, 1229, 1796, 2627, 3845, 5630, 8246, 12080, 17699, 25934, 38003, 55691, 81614, 119606, 175286, 256889, 376484, 551759, 808637, 1185110, 1736858, 2545484, 3730583, 5467430, 8012903, 11743475

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>8.

Empirical g.f.: x*(36 - 34*x + x^2 - 29*x^3 + 5*x^4 + 7*x^5 + 2*x^6 + x^7) / ((1 - x)*(1 - x - x^3)). - Colin Barker, Dec 21 2018

Example

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

Crossrefs

Column 2 of A257447.

Sequence in context: A160553 A295751 A031317 * A181457 A261380 A337861

Adjacent sequences: A257438 A257439 A257440 * A257442 A257443 A257444

Keyword

nonn

Author

R. H. Hardin, Apr 23 2015

Status

approved