OFFSET
1,1
COMMENTS
Every 0 is next to 0 4's, every 1 is next to 1 3's, every 2 is next to 2 0's, every 3 is next to 3 2's, every 4 is next to 4 1's
Column 3 of A196974
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) +5*a(n-2) +2*a(n-3) -2*a(n-4) -11*a(n-5) +a(n-6) +36*a(n-7) +50*a(n-8) +20*a(n-9) -20*a(n-10) -49*a(n-11) -42*a(n-12) -20*a(n-13) +4*a(n-14) +9*a(n-15) +2*a(n-16)
EXAMPLE
Some solutions for n=4
..0..2..0....0..0..0....2..0..0....0..0..2....0..0..2....0..2..0....0..0..2
..2..3..2....2..3..2....0..2..2....0..0..0....2..2..0....0..2..2....2..2..0
..0..0..0....0..2..0....2..3..0....2..2..0....0..3..2....0..0..0....0..2..0
..0..0..0....0..2..0....0..2..0....0..2..0....0..2..0....0..0..2....0..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 08 2011
STATUS
approved