A204380 Number of (n+2) X 9 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.

439, 193, 205, 217, 241, 283, 347, 453, 625, 901, 1349, 2075, 3247, 5145, 8217, 13185, 21225, 34235, 55283, 89341, 144449, 233613, 377885, 611323, 989031, 1600177, 2589033, 4189033, 6777889, 10966747, 17744459, 28711029, 46455313, 75166165

Offset

1,1

Comments

Column 7 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*(439 - 246*x - 427*x^2 - 620*x^3 + 65*x^4 + 252*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..0..0..0....0..0..1..0..1..0..0..0..0
..1..1..1..1..1..1..1..1..1....0..0..1..0..1..0..0..1..0
..0..0..0..0..0..0..0..0..0....0..0..1..0..1..0..0..1..0
..1..1..1..1..1..1..1..1..1....0..0..1..0..1..0..0..1..0
..0..0..0..0..0..0..0..0..0....0..0..1..0..1..0..0..1..0

Crossrefs

Cf. A204381.

Sequence in context: A043447 A006911 A222877 * A185683 A142753 A142141

Adjacent sequences: A204377 A204378 A204379 * A204381 A204382 A204383

Keyword

nonn

Author

R. H. Hardin, Jan 14 2012

Status

approved