A243604 Number of length n+2 0..7 arrays with no three elements in a row with pattern aba (with a!=b) and new values 0..7 introduced in 0..7 order.

4, 10, 29, 97, 366, 1534, 7049, 35129, 187993, 1069914, 6413136, 40104257, 259358085, 1721368017, 11650893890, 80015045418, 555433766065, 3885803906493, 27339242339942, 193138394368496, 1368463903086546, 9716805805575427

Offset: 1

Author

R. H. Hardin, Jun 07 2014

Keywords

• nonn

Comments

Column 7 of A243607

Examples

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

Links

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

Formula

Empirical: a(n) = 23*a(n-1) -206*a(n-2) +894*a(n-3) -1814*a(n-4) +902*a(n-5) +1940*a(n-6) -1536*a(n-7) -1306*a(n-8) +394*a(n-9) +526*a(n-10) +162*a(n-11) +21*a(n-12) +a(n-13)