A232590 Number of (1+1)X(n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or antidiagonally, with no adjacent elements equal.

0, 10, 2, 26, 20, 70, 90, 210, 336, 674, 1178, 2234, 4036, 7502, 13714, 25314, 46464, 85562, 157266, 289370, 532116, 978838, 1800234, 3311282, 6090256, 11201874, 20603306, 37895546, 69700612, 128199582, 235795618, 433695938, 797691008

Offset: 1

Author

R. H. Hardin, Nov 26 2013

Keywords

• nonn

Comments

Row 1 of A232589

Examples

			Some solutions for n=7
..0..1..2..1..0..1..2..0....0..1..2..1..2..1..0..2....0..1..2..1..2..0..1..2
..2..1..0..1..2..0..1..2....0..1..0..1..0..2..1..0....2..1..0..1..2..0..1..0
		

Links

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

Formula

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

Empirical: G.f.: -2*x^2*(5+6*x+4*x^2+x^3) / ( (x^3+x^2+x-1)*(1+x)^2 ). - R. J. Mathar, Nov 23 2014