A252534 Number of (2+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.

595, 337, 341, 462, 706, 1000, 1468, 2420, 3480, 5240, 8872, 12880, 19696, 33872, 49440, 76256, 132256, 193600, 299968, 522560, 766080, 1189760, 2077312, 3047680, 4738816, 8283392, 12157440, 18914816, 33081856, 48563200, 75578368, 132224000

Offset: 1

Author

R. H. Hardin, Dec 18 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 2 of A252532.

Formula

Empirical: a(n) = 6*a(n-3) - 8*a(n-6) for n>10.

Empirical g.f.: x*(595 + 337*x + 341*x^2 - 3108*x^3 - 1316*x^4 - 1046*x^5 + 3456*x^6 + 880*x^7 + 208*x^8 + 128*x^9) / ((1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Dec 04 2018