A266009 Number of n X 5 integer arrays with each element equal to the number of horizontal and antidiagonal neighbors equal to itself.

1, 4, 11, 27, 70, 182, 483, 1281, 3389, 8986, 23818, 63151, 167404, 443816, 1176578, 3119246, 8269369, 21922921, 58119638, 154080691, 408482159, 1082924551, 2870933873, 7611114236, 20177774274, 53493165081, 141815376408, 375965811006

Offset

1,2

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 2*a(n-2) - a(n-3) + 2*a(n-4) - 3*a(n-5) - a(n-6) for n>12.

Empirical g.f.: x*(1 + 2*x + x^2 - 2*x^3 - 4*x^4 - 6*x^5 - 3*x^6 + 4*x^7 - 5*x^8 + 2*x^9 - x^10 + x^11) / ((1 - x)*(1 + x^2)*(1 - x - 4*x^2 - x^3)). - Colin Barker, Jan 09 2019

Example

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

Crossrefs

Column 5 of A266012.

Sequence in context: A108985 A014151 A176759 * A096124 A269076 A282641

Adjacent sequences: A266006 A266007 A266008 * A266010 A266011 A266012

Keyword

nonn

Author

R. H. Hardin, Dec 20 2015

Status

approved