A256741 Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum 3 and no antidiagonal sum 3 and no row sum 0 and no column sum 0.

153, 393, 857, 2065, 5255, 12914, 31032, 75634, 185630, 453792, 1107035, 2701934, 6602744, 16133440, 39398362, 96225937, 235055049, 574159002, 1402439544, 3425537766, 8367239407, 20438044264, 49921902827, 121939228872, 297849461916

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 2*a(n-2) + 5*a(n-3) + a(n-5) - 14*a(n-6) - 19*a(n-7) + 3*a(n-8) + 3*a(n-9) for n>12.

Empirical g.f.: x*(153 + 240*x + 158*x^2 - 343*x^3 - 489*x^4 - 909*x^5 - 968*x^6 + 51*x^7 + 303*x^8 + 34*x^9 - 46*x^10 + 8*x^11) / (1 - x - 2*x^2 - 5*x^3 - x^5 + 14*x^6 + 19*x^7 - 3*x^8 - 3*x^9). - Colin Barker, Dec 20 2018

Example

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

Crossrefs

Column 1 of A256748.

Sequence in context: A271730 A056733 A256748 * A349696 A246629 A371082

Adjacent sequences: A256738 A256739 A256740 * A256742 A256743 A256744

Keyword

nonn

Author

R. H. Hardin, Apr 09 2015

Status

approved