A203791 Number of (n+1) X 4 0..3 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements.

5488, 142192, 3784288, 101071600, 2700695728, 72168659104, 1928524187248, 51534966781936, 1377142783787488, 36800688925407472, 983406168592794928, 26279064902536667680, 702242139855909029488, 18765660986075071030384

Offset

1,1

Comments

Column 3 of A203796.

Links

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

Formula

Empirical: a(n) = 31*a(n-1) -117*a(n-2) +72*a(n-3).

Empirical g.f.: 16*x*(343 - 1746*x + 1152*x^2) / (1 - 31*x + 117*x^2 - 72*x^3). - Colin Barker, Jun 05 2018

Example

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

Crossrefs

Cf. A203796.

Sequence in context: A251962 A251956 A232153 * A137816 A138760 A251885

Adjacent sequences: A203788 A203789 A203790 * A203792 A203793 A203794

Keyword

nonn

Author

R. H. Hardin, Jan 05 2012

Status

approved