A251892 Number of (n+2) X (6+2) 0..3 arrays with every 3 X 3 subblock row and column sum not 2 3 6 or 7 and every diagonal and antidiagonal sum 2 3 6 or 7.

1752, 790, 1636, 2660, 6072, 9836, 17774, 38612, 70970, 132530, 284490, 536930, 1021634, 2178338, 4172162, 8018690, 17036418, 32884226, 63532034, 134730242, 261101570, 505786370, 1071597570, 2080923650, 4036411394, 8547803138

Offset

1,1

Comments

Column 6 of A251894.

Links

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

Formula

Empirical: a(n) = a(n-1) + 12*a(n-3) - 12*a(n-4) - 32*a(n-6) + 32*a(n-7) for n>12.

Empirical g.f.: 2*x*(876 - 481*x + 423*x^2 - 10000*x^3 + 7478*x^4 - 3194*x^5 + 25857*x^6 - 25445*x^7 + 7131*x^8 - 464*x^9 + 5544*x^10 - 7704*x^11) / ((1 - x)*(1 - 2*x)*(1 + 2*x + 4*x^2)*(1 - 4*x^3)). - Colin Barker, Mar 20 2018

Example

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

Crossrefs

Cf. A251894.

Sequence in context: A201801 A172833 A172882 * A143994 A157325 A223448

Adjacent sequences: A251889 A251890 A251891 * A251893 A251894 A251895

Keyword

nonn

Author

R. H. Hardin, Dec 10 2014

Status

approved