OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 7*a(n-2) - 3*a(n-3) + 3*a(n-4) - 7*a(n-5) + 2*a(n-6) - 2*a(n-7) + 2*a(n-8) for n>12.
Empirical g.f.: x*(1 + 15*x + 51*x^2 - 29*x^3 + x^4 - 55*x^5 + 14*x^6 - 4*x^7 + 20*x^8 - 2*x^10 - 2*x^11) / (1 - x - 7*x^2 + 3*x^3 - 3*x^4 + 7*x^5 - 2*x^6 + 2*x^7 - 2*x^8). - Colin Barker, Oct 05 2018
EXAMPLE
Some solutions for n=7.
..0..1..2..1..0..1..0....1..2..1..2..1..2..1....0..1..2..1..2..1..0
..0..1..2..1..2..1..2....1..2..1..0..1..2..1....0..1..2..1..2..1..2
..0..1..0..1..0..1..2....1..2..1..0..1..0..2....0..1..2..1..0..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 22 2013
STATUS
approved