A232591 Number of (2+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.

2, 34, 12, 152, 108, 690, 744, 3232, 4516, 15592, 25724, 76914, 141516, 385622, 762648, 1955944, 4058152, 10001440, 21421592, 51425362, 112496648, 265415854, 588810972, 1373336224, 3075128652, 7118096080, 16037159652, 36935382354

Offset: 1

Author

R. H. Hardin, Nov 26 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 2 of A232589.

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) for n>10.

Empirical g.f.: x*(1 + 17*x + x^2 - 13*x^3 - 41*x^4 + 4*x^5 + 23*x^6 + 20*x^7 + 2*x^8 - x^9) / (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). - Colin Barker, Oct 05 2018