A252011 Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row and column sum 1 3 6 or 8 and every diagonal and antidiagonal sum not 1 3 6 or 8.

1618, 2002, 2170, 3814, 8482, 16994, 29954, 67714, 136002, 239874, 541762, 1088002, 1918978, 4334082, 8704002, 15351810, 34672642, 69632002, 122814466, 277381122, 557056002, 982515714, 2219048962, 4456448002, 7860125698, 17752391682

Offset

1,1

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>12.

Empirical g.f.: 2*x*(809 + 192*x + 84*x^2 - 5650*x^3 + 798*x^4 + 3584*x^5 - 96*x^6 + 208*x^7 + 96*x^8 + 96*x^9 - 96*x^10 - 32*x^11) / ((1 - x)*(1 - 2*x)*(1 + 2*x + 4*x^2)). - Colin Barker, Dec 01 2018

Example

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

Crossrefs

Column 4 of A252015.

Sequence in context: A236060 A231048 A231423 * A277111 A345597 A345856

Adjacent sequences: A252008 A252009 A252010 * A252012 A252013 A252014

Keyword

nonn

Author

R. H. Hardin, Dec 12 2014

Status

approved