A204283 Number of (n+2) X 9 0..2 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..2 introduced in row major order.

29731, 1883, 1990, 1914, 2168, 2860, 3664, 6784, 15304, 36408, 95912, 258472, 698248, 1903432, 5196040, 14182920, 38742920, 105842056, 289142920, 789944968, 2158161544, 5896163976, 16108606088, 44009516680, 120236152456, 328491253384

Offset

1,1

Comments

Column 7 of A204284.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -6*a(n-4) +4*a(n-6) for n>8.

Empirical g.f.: x*(29731 - 87310*x - 3659*x^2 - 4056*x^3 + 174812*x^4 + 7654*x^5 - 111900*x^6 - 256*x^7) / ((1 - x)*(1 - 2*x - 2*x^2)*(1 - 2*x^3)). - Colin Barker, Jun 06 2018

Example

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

Crossrefs

Cf. A204284.

Sequence in context: A203502 A228544 A206203 * A251054 A206070 A056747

Adjacent sequences: A204280 A204281 A204282 * A204284 A204285 A204286

Keyword

nonn

Author

R. H. Hardin, Jan 13 2012

Status

approved