A203730 Number of (n+1) X 4 0..7 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements.

216000, 19071424, 1754118528, 161916229056, 14950234495680, 1380434809882752, 127463146627838400, 11769375979053945792, 1086731469961775989632, 100343917224754801007040, 9265307946968320001885376

Offset

1,1

Comments

Column 3 of A203732.

Links

R. H. Hardin, Table of n, a(n) for n = 1..168

Formula

Empirical: a(n) = 99*a(n-1) -609*a(n-2) -588*a(n-3).

Empirical g.f.: 64*x*(3375 - 36134*x - 37632*x^2) / (1 - 99*x + 609*x^2 + 588*x^3). - Colin Barker, Jun 04 2018

Example

Some solutions for n=4:
..2..3..7..4....3..2..0..1....4..0..7..0....1..5..1..7....1..5..7..2
..4..2..3..7....0..3..2..0....1..4..0..4....3..1..2..1....0..1..5..7
..6..4..2..3....7..0..3..2....2..1..4..4....4..3..1..1....1..7..1..5
..6..6..4..2....1..7..0..3....7..2..1..4....3..1..4..1....1..1..1..1
..1..6..6..4....5..1..7..0....2..3..2..1....5..3..1..7....4..1..0..1

Crossrefs

Cf. A203732.

Sequence in context: A272410 A118875 A205924 * A273219 A351662 A251804

Adjacent sequences: A203727 A203728 A203729 * A203731 A203732 A203733

Keyword

nonn

Author

R. H. Hardin, Jan 05 2012

Status

approved