A232400 Number of (n+1)X(2+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or vertically, with no adjacent elements equal

4, 16, 20, 72, 124, 356, 664, 1808, 3572, 9148, 19040, 46784, 100412, 240716, 527128, 1242560, 2758676, 6430140, 14405648, 33331296, 75121004, 172964748, 391375112, 898217344, 2037797060, 4666779068, 10606071296, 24254561056, 55186525212

Offset

1,1

Comments

Column 2 of A232406

Links

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

Formula

Empirical: a(n) = 5*a(n-2) +4*a(n-3) -3*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) +6*a(n-8) +2*a(n-9).

Empirical: G.f.: -4*x*(1+4*x-6*x^3-7*x^4+3*x^5+5*x^6+3*x^7+x^8) / ( -1 +5*x^2 +4*x^3 -3*x^4 -12*x^5 -3*x^6 +6*x^7 +6*x^8 +2*x^9 ). - R. J. Mathar, Nov 27 2013

Example

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

Crossrefs

Sequence in context: A326788 A039943 A193996 * A345763 A354712 A067671

Adjacent sequences: A232397 A232398 A232399 * A232401 A232402 A232403

Keyword

nonn

Author

R. H. Hardin, Nov 23 2013

Status

approved