A232401 Number of (n+1)X(3+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

8, 20, 52, 176, 484, 1500, 4416, 13220, 39524, 117892, 352408, 1052272, 3143372, 9389000, 28044172, 83767512, 250208044, 747361736, 2232332800, 6667874240, 19916631536, 59490043068, 177693992608, 530763654360, 1585366282080

Offset

1,1

Comments

Column 3 of A232406

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +4*a(n-2) +a(n-3) -10*a(n-4) -9*a(n-5) +16*a(n-7) +4*a(n-8) -a(n-9) -4*a(n-10) -a(n-11) -a(n-12)

Example

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

Crossrefs

Sequence in context: A361073 A361215 A205219 * A036835 A295933 A360222

Adjacent sequences: A232398 A232399 A232400 * A232402 A232403 A232404

Keyword

nonn

Author

R. H. Hardin, Nov 23 2013

Status

approved