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

1,1

Comments

Column 2 of A200668

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)

Example

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

Crossrefs

Sequence in context: A018183 A196787 A367217 * A371792 A264507 A137711

Adjacent sequences: A200659 A200660 A200661 * A200663 A200664 A200665

Keyword

nonn

Author

R. H. Hardin Nov 20 2011

Status

approved