A252112 Number of (n+2) X (6+2) 0..3 arrays with every 3 X 3 subblock row and column sum equal to 0 2 3 6 or 7 and every 3 X 3 diagonal and antidiagonal sum not equal to 0 2 3 6 or 7.

2058, 788, 1634, 2658, 6070, 9834, 17772, 38610, 70968, 132528, 284488, 536928, 1021632, 2178336, 4172160, 8018688, 17036416, 32884224, 63532032, 134730240, 261101568, 505786368, 1071597568, 2080923648, 4036411392, 8547803136

Offset

1,1

Links

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

Formula

Empirical: a(n) = 12*a(n-3) - 32*a(n-6) for n>11.

Empirical g.f.: 2*x*(1029 + 394*x + 817*x^2 - 11019*x^3 - 1693*x^4 - 4887*x^5 + 25866*x^6 - 4507*x^7 + 2624*x^8 + 2160*x^9 + 7704*x^10) / ((1 - 2*x)*(1 + 2*x + 4*x^2)*(1 - 4*x^3)). - Colin Barker, Dec 01 2018

Example

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

Crossrefs

Column 6 of A252114.

Sequence in context: A168227 A321488 A074996 * A045055 A255335 A255423

Adjacent sequences: A252109 A252110 A252111 * A252113 A252114 A252115

Keyword

nonn

Author

R. H. Hardin, Dec 14 2014

Status

approved