A252526 Number of (n+2) X (2+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.

730, 337, 334, 426, 676, 964, 1344, 2312, 3336, 4800, 8464, 12304, 18048, 32288, 47136, 69888, 126016, 184384, 274944, 497792, 729216, 1090560, 1978624, 2900224, 4343808, 7889408, 11567616, 17338368, 31507456, 46203904, 69279744, 125929472

Offset: 1

Author

R. H. Hardin, Dec 18 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 2 of A252532.

Formula

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

Empirical g.f.: x*(730 + 337*x + 334*x^2 - 3954*x^3 - 1346*x^4 - 1040*x^5 + 4628*x^6 + 952*x^7 + 224*x^8 + 144*x^9) / ((1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Dec 04 2018