A252717 Number of (n+2) X (6+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.

175, 91, 110, 132, 191, 262, 324, 478, 664, 828, 1231, 1718, 2148, 3203, 4478, 5604, 8366, 11704, 14652, 21883, 30622, 38340, 57271, 80150, 100356, 149918, 209816, 262716, 392471, 549286, 687780, 1027483, 1438030, 1800612, 2689966, 3764792

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) - 3*a(n-4) - a(n-6) + a(n-7) for n>9.

Empirical g.f.: x*(175 - 84*x + 19*x^2 - 503*x^3 + 311*x^4 + 14*x^5 + 171*x^6 - 107*x^7 - 8*x^8) / ((1 - x)*(1 - 3*x^3 + x^6)). - Colin Barker, Dec 05 2018

Example

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

Crossrefs

Column 6 of A252719.

Sequence in context: A185525 A224433 A213866 * A187425 A186218 A245035

Adjacent sequences: A252714 A252715 A252716 * A252718 A252719 A252720

Keyword

nonn

Author

R. H. Hardin, Dec 20 2014

Status

approved