A205621 Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock in a row having an equal number of equal diagonal or equal antidiagonal elements, adjacent rows differing in this number, and new values 0..2 introduced in row major order.

194, 1512, 13068, 113592, 992088, 8636544, 75419136, 656729088, 5733618048, 49937319936, 435896552448, 3797147043840, 33139377911808, 288724641841152, 2519477853880320, 21953583883419648, 191549577961635840

Offset

1,1

Comments

Column 3 of A205626.

Links

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

Formula

Empirical: a(n) = 72*a(n-2) + 48*a(n-3) - 112*a(n-4) for n>5.

Empirical g.f.: 2*x*(97 + 756*x - 450*x^2 - 2292*x^3 + 172*x^4) / (1 - 72*x^2 - 48*x^3 + 112*x^4). - Colin Barker, Jun 12 2018

Example

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

Crossrefs

Cf. A205626.

Sequence in context: A248549 A278123 A158224 * A205356 A281807 A220160

Adjacent sequences: A205618 A205619 A205620 * A205622 A205623 A205624

Keyword

nonn

Author

R. H. Hardin, Jan 29 2012

Status

approved