OFFSET
1,2
COMMENTS
Every 0 is next to 0 0's, every 1 is next to 1 3's, every 2 is next to 2 1's, every 3 is next to 3 1's, every 4 is next to 4 1's
Column 3 of A197623
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-2) +2*a(n-3) +19*a(n-4) +31*a(n-5) +39*a(n-6) +74*a(n-7) +82*a(n-8) -66*a(n-9) -608*a(n-10) -91*a(n-11) -672*a(n-12) +57*a(n-13) -2166*a(n-14) +1531*a(n-15) +346*a(n-16) -20*a(n-17) +50*a(n-18) -12*a(n-19) -2*a(n-20)
EXAMPLE
Some solutions for n=4
..2..1..0....0..2..1....2..1..2....1..3..1....0..1..2....2..1..0....1..3..1
..1..3..1....1..1..3....1..3..1....0..1..2....1..3..1....1..3..1....2..1..0
..1..3..1....3..1..1....1..3..1....2..1..2....1..3..1....1..3..1....2..1..2
..2..1..2....1..2..0....2..1..0....1..3..1....0..1..0....0..1..2....1..3..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 16 2011
STATUS
approved