A204750 Number of (n+2) X 6 0..1 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..1 introduced in row major order.

188, 28, 27, 32, 40, 53, 74, 108, 163, 252, 396, 629, 1006, 1616, 2603, 4200, 6784, 10965, 17730, 28676, 46387, 75044, 121412, 196437, 317830, 514248, 832059, 1346288, 2178328, 3524597, 5702906, 9227484, 14930371, 24157836, 39088188

Offset

1,1

Comments

Column 4 of A204754.

Links

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

Formula

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

Empirical g.f.: x*(188 - 348*x - 29*x^2 + 166*x^3 + 4*x^4) / ((1 - x)*(1 - x - x^2)). - Colin Barker, Jun 09 2018

Example

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

Crossrefs

Cf. A204754.

Sequence in context: A198905 A198252 A070257 * A015986 A065212 A044998

Adjacent sequences: A204747 A204748 A204749 * A204751 A204752 A204753

Keyword

nonn

Author

R. H. Hardin, Jan 18 2012

Status

approved