A232937 Number of n X 4 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, vertically or antidiagonally.

24, 56, 252, 1048, 4458, 18850, 79810, 337850, 1430144, 6054098, 25627862, 108487018, 459242866, 1944049234, 8229473620, 34836688334, 147469316688, 624261386538, 2642599067830, 11186547787492, 47354459831826

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 10*a(n-2) + 15*a(n-3) + 4*a(n-4) - 6*a(n-5) - a(n-6) + 3*a(n-7) - a(n-8) for n>9.

Empirical g.f.: 2*x*(12 + 16*x - 22*x^2 - 62*x^3 - 23*x^4 + 26*x^5 + 6*x^6 - 13*x^7 + 4*x^8) / (1 - x - 10*x^2 - 15*x^3 - 4*x^4 + 6*x^5 + x^6 - 3*x^7 + x^8). - Colin Barker, Oct 06 2018

Example

Some solutions for n=5:
..0..1..0..0....2..2..2..2....2..1..2..1....2..2..2..2....1..0..0..0
..0..0..0..0....2..2..2..2....2..2..2..2....1..2..2..2....0..0..0..0
..1..0..1..0....1..2..2..2....2..2..2..1....2..2..2..1....0..0..1..0
..0..0..0..0....2..2..2..2....2..2..2..2....2..1..2..2....0..0..0..0
..1..0..0..1....2..2..2..2....1..2..1..2....2..2..1..2....0..1..0..0

Crossrefs

Column 4 of A232941.

Sequence in context: A043978 A211461 A208086 * A190104 A255968 A211325

Adjacent sequences: A232934 A232935 A232936 * A232938 A232939 A232940

Keyword

nonn

Author

R. H. Hardin, Dec 02 2013

Status

approved