A200662 Number of 0..2 arrays x(0..n-1) of n elements with each no smaller than the sum of its three previous neighbors modulo 3.

3, 6, 12, 24, 46, 89, 176, 350, 697, 1391, 2780, 5555, 11098, 22170, 44288, 88472, 176729, 353032, 705224, 1408771, 2814203, 5621746, 11230193, 22433834, 44814616, 89523251, 178834811, 357246713, 713648606, 1425609609, 2847847987, 5688961529

Offset: 1

Author

R. H. Hardin Nov 20 2011

Keywords

• nonn

Comments

Column 2 of A200668

Examples

			Some solutions for n=6
..0....2....0....0....1....0....0....2....0....1....1....0....1....1....1....1
..1....2....0....0....1....0....1....2....1....2....1....0....2....1....2....2
..2....2....2....1....2....0....2....2....1....1....2....2....0....2....0....0
..0....2....2....2....1....2....0....0....2....1....2....2....2....1....1....2
..1....2....2....0....1....2....1....1....2....2....2....1....1....1....0....1
..2....0....1....2....2....2....1....0....2....2....0....2....0....1....2....2
		

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -3*a(n-2) +4*a(n-3) -6*a(n-4) +7*a(n-5) -9*a(n-6) +8*a(n-7) -6*a(n-8) +5*a(n-9) -4*a(n-10) +5*a(n-11) -5*a(n-12) +2*a(n-14) -3*a(n-15) +2*a(n-16) +a(n-17) -2*a(n-18) +5*a(n-19) -3*a(n-20) +a(n-21) -a(n-22) -a(n-24) +a(n-25) -a(n-26) +a(n-27)