A267638 Number of nX2 0..1 arrays with every repeated value in every row and column unequal to the previous repeated value, and new values introduced in row-major sequential order.

2, 8, 18, 50, 98, 242, 450, 1058, 1922, 4418, 7938, 18050, 32258, 72962, 130050, 293378, 522242, 1176578, 2093058, 4712450, 8380418, 18862082, 33538050, 75472898, 134184962, 301940738, 536805378, 1207861250, 2147352578, 4831641602

Offset

1,1

Comments

Column 2 of A267644.

Links

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

Formula

Empirical: a(n) = a(n-1) +6*a(n-2) -6*a(n-3) -8*a(n-4) +8*a(n-5).

Empirical: G.f.: -2*x*(1+3*x-x^2-2*x^3+2*x^4) / ( (x-1)*(2*x+1)*(2*x-1)*(2*x^2-1) ). - R. J. Mathar, Jan 26 2016

Example

Some solutions for n=6
..0..1....0..0....0..0....0..1....0..1....0..1....0..1....0..0....0..0....0..0
..1..0....1..1....1..0....1..0....0..1....1..1....1..1....0..1....1..1....0..1
..0..1....1..1....0..1....1..1....1..0....0..0....0..0....1..0....0..0....1..0
..1..0....0..0....1..1....0..0....0..0....0..1....0..0....1..0....1..1....1..0
..1..0....1..1....0..0....0..1....1..1....1..0....1..1....0..1....0..0....0..1
..0..1....0..0....0..0....1..1....1..0....0..0....1..1....0..0....1..0....1..1

Crossrefs

Cf. A267644.

Sequence in context: A332217 A249763 A114723 * A153335 A119853 A136201

Adjacent sequences: A267635 A267636 A267637 * A267639 A267640 A267641

Keyword

nonn

Author

R. H. Hardin, Jan 18 2016

Status

approved