A203881 Number of (n+1) X 3 0..6 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements.

8281, 254359, 7501753, 222645367, 6601376089, 195759462871, 5804976472057, 172139217677623, 5104567195084441, 151369391916622999, 4488665070837227833, 133105602855424669687, 3947075851161154183129, 117045469473077458995031

Offset

1,1

Comments

Column 2 of A203887.

Links

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

Formula

Empirical: a(n) = 25*a(n-1) +138*a(n-2).

Empirical g.f.: 49*x*(169 + 966*x) / (1 - 25*x - 138*x^2). - Colin Barker, Jun 05 2018

Example

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

Crossrefs

Cf. A203887.

Sequence in context: A252581 A271748 A064014 * A145527 A054215 A031589

Adjacent sequences: A203878 A203879 A203880 * A203882 A203883 A203884

Keyword

nonn

Author

R. H. Hardin, Jan 07 2012

Status

approved