A252538 Number of (6+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 3 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 3 6 or 7.

649, 964, 1748, 2504, 7136, 13184, 19232, 54656, 102272, 150656, 427520, 805376, 1192448, 3381248, 6391808, 9488384, 26894336, 50929664, 75702272, 214532096, 406618112, 604798976, 1713766400, 3249668096, 4835115008, 13700169728

Offset: 1

Author

R. H. Hardin, Dec 18 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 6 of A252532.

Formula

Empirical: a(n) = 12*a(n-3) - 32*a(n-6) for n>8.

Empirical g.f.: x*(649 + 964*x + 1748*x^2 - 5284*x^3 - 4432*x^4 - 7792*x^5 + 9952*x^6 - 128*x^7) / ((1 - 2*x)*(1 + 2*x + 4*x^2)*(1 - 4*x^3)). - Colin Barker, Dec 04 2018