A204566 Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..3 introduced in row major order.

42, 482, 6112, 80518, 1075080, 14421190, 193752824, 2604524150, 35017728648, 470841185510, 6330966828952, 85127273980246, 1144638803080104, 15391060969557190, 206951592970169528, 2782716926395505462

Offset

1,1

Comments

Column 2 of A204572.

Links

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

Formula

Empirical: a(n) = 19*a(n-1) - 79*a(n-2) + 57*a(n-3) + 16*a(n-4) - 12*a(n-5).

Empirical g.f.: 2*x*(21 - 158*x + 136*x^2 + 37*x^3 - 30*x^4) / ((1 - x)*(1 - 5*x + 2*x^2)*(1 - 13*x - 6*x^2)). - Colin Barker, Jun 07 2018

Example

Some solutions for n=4:
..0..0..0....0..0..0....0..1..0....0..1..0....0..1..1....0..0..0....0..0..1
..0..0..0....0..0..1....1..0..0....2..0..1....2..0..1....0..0..1....2..0..0
..1..0..1....2..0..0....1..1..0....0..2..0....3..2..0....1..0..0....3..2..0
..0..1..0....3..2..0....0..1..1....1..0..1....2..0..0....0..0..2....0..3..2
..1..0..0....1..3..2....1..0..1....3..1..0....1..2..0....0..0..0....1..0..3

Crossrefs

Cf. A204572.

Sequence in context: A216109 A216111 A216113 * A348833 A249233 A249234

Adjacent sequences: A204563 A204564 A204565 * A204567 A204568 A204569

Keyword

nonn

Author

R. H. Hardin, Jan 16 2012

Status

approved