A252336 Number of (n+2) X (1+2) 0..2 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 2 3 or 4.

52, 108, 234, 538, 1202, 2612, 5706, 12616, 27880, 61330, 134854, 297006, 654392, 1441026, 3172540, 6985816, 15384194, 33877498, 74597994, 164266052, 361723666, 796536048, 1754004560, 3862386738, 8505149742, 18728734382, 41241504360

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 3*a(n-3) + 4*a(n-4) + 4*a(n-5) + 2*a(n-6) for n>7.

Empirical g.f.: 2*x*(26 + 28*x + 63*x^2 + 74*x^3 + 66*x^4 + 34*x^5 + 4*x^6) / (1 - x - 3*x^3 - 4*x^4 - 4*x^5 - 2*x^6). - Colin Barker, Dec 03 2018

Example

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

Crossrefs

Column 1 of A252343.

Sequence in context: A335479 A272140 A252343 * A044239 A044620 A209988

Adjacent sequences: A252333 A252334 A252335 * A252337 A252338 A252339

Keyword

nonn

Author

R. H. Hardin, Dec 16 2014

Status

approved