OFFSET
1,2
COMMENTS
Every 0 is next to 0 4's, every 1 is next to 1 3's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 2's.
Column 3 of A196904.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) +7*a(n-2) +8*a(n-3) -2*a(n-4) -33*a(n-5) +2*a(n-6) -6*a(n-7) -14*a(n-8) +a(n-9) +2*a(n-10).
Empirical g.f.: x*(1 + x + 7*x^2 + 2*x^3 - 18*x^4 - 14*x^5 - 17*x^6 + 11*x^7 + 7*x^8 - 2*x^9) / (1 - 2*x - 7*x^2 - 8*x^3 + 2*x^4 + 33*x^5 - 2*x^6 + 6*x^7 + 14*x^8 - x^9 - 2*x^10). - Colin Barker, May 09 2018
EXAMPLE
Some solutions for n=4:
..0..3..0....0..3..0....0..3..0....0..0..0....0..0..0....0..3..0....0..1..0
..3..0..0....0..0..3....3..0..3....0..0..0....1..3..0....3..0..3....0..3..0
..0..0..3....3..0..0....0..0..0....3..0..0....0..0..3....0..3..0....3..0..3
..0..3..0....0..3..0....0..0..0....0..0..0....0..0..0....0..1..0....0..3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 07 2011
STATUS
approved