A252543 Number of (n+2) X (1+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 1 3 4 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 1 3 4 6 or 7.

478, 850, 2142, 4644, 13104, 33852, 73800, 208992, 540792, 1179792, 3342528, 8650992, 18874656, 53477760, 138412512, 301990464, 855638784, 2214593472, 4831839360, 13690209792, 35433482112, 77309413632, 219043335168

Offset

1,1

Links

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

Formula

Empirical: a(n) = 18*a(n-3) - 32*a(n-6) for n>8.

Empirical g.f.: 2*x*(239 + 425*x + 1071*x^2 - 1980*x^3 - 1098*x^4 - 2352*x^5 + 2752*x^6 + 160*x^7) / ((1 - 2*x^3)*(1 - 16*x^3)). - Colin Barker, Dec 05 2018

Example

Some solutions for n=4:
..0..3..1....0..1..3....0..1..0....2..0..2....0..3..1....2..0..2....0..1..3
..2..1..1....1..1..2....1..1..2....2..2..3....1..3..0....2..2..3....0..0..1
..3..1..3....1..3..0....1..3..0....1..3..3....1..2..1....1..0..0....2..1..1
..3..0..1....0..1..3....3..1..0....2..3..2....3..3..1....2..3..2....0..1..3
..2..1..1....1..1..2....1..1..2....2..2..0....1..0..3....2..2..3....0..3..1
..3..1..0....1..0..3....1..0..0....1..3..0....1..2..1....1..0..0....2..1..1

Crossrefs

Column 1 of A252544.

Sequence in context: A352265 A020375 A031788 * A235083 A252544 A252545

Adjacent sequences: A252540 A252541 A252542 * A252544 A252545 A252546

Keyword

nonn

Author

R. H. Hardin, Dec 18 2014

Status

approved