A251893 Number of (n+2) X (7+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.

2146, 1182, 2478, 4490, 11762, 17774, 33218, 84866, 142178, 265730, 678914, 1137410, 2125826, 5431298, 9099266, 17006594, 43450370, 72794114, 136052738, 347602946, 582352898, 1088421890, 2780823554, 4658823170, 8707375106

Offset

1,1

Comments

Column 7 of A251894.

Links

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

Formula

Empirical: a(n) = a(n-1) + 8*a(n-3) - 8*a(n-4) for n>9.

Empirical g.f.: 2*x*(1073 - 482*x + 648*x^2 - 7578*x^3 + 7492*x^4 - 2178*x^5 - 326*x^6 - 3264*x^7 + 4608*x^8) / ((1 - x)*(1 - 2*x)*(1 + 2*x + 4*x^2)). - Colin Barker, Mar 20 2018

Example

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

Crossrefs

Cf. A251894.

Sequence in context: A118576 A259413 A294751 * A251870 A291135 A251852

Adjacent sequences: A251890 A251891 A251892 * A251894 A251895 A251896

Keyword

nonn

Author

R. H. Hardin, Dec 10 2014

Status

approved