A204378 Number of (n+2) X 7 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..1 introduced in row major order.

182, 88, 98, 111, 136, 176, 241, 348, 518, 795, 1244, 1968, 3141, 5040, 8110, 13079, 21120, 34128, 55177, 89236, 144342, 233507, 377780, 611216, 988925, 1600072, 2588926, 4188927, 6777784, 10966640, 17744353, 28710924, 46455206, 75166059

Offset

1,1

Comments

Column 5 of A204381.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +a(n-3) -a(n-4) -a(n-5) for n>8.

Empirical g.f.: x*(182 - 94*x - 172*x^2 - 257*x^3 + 21*x^4 + 101*x^5 + 4*x^6 + 4*x^7) / ((1 - x)*(1 - x - x^2)*(1 + x + x^2)). - Colin Barker, Jun 07 2018

Example

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

Crossrefs

Cf. A204381.

Sequence in context: A185824 A324271 A265997 * A054572 A054985 A124185

Adjacent sequences: A204375 A204376 A204377 * A204379 A204380 A204381

Keyword

nonn

Author

R. H. Hardin, Jan 14 2012

Status

approved