OFFSET
1,1
COMMENTS
Every 0 is next to 0 2's, every 1 is next to 1 1's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 0's
Column 3 of A197450
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) +12*a(n-2) +45*a(n-3) +61*a(n-4) +20*a(n-5) -129*a(n-6) -324*a(n-7) -344*a(n-8) -166*a(n-9) +61*a(n-10) +268*a(n-11) +360*a(n-12) +307*a(n-13) +240*a(n-14) +92*a(n-15) -97*a(n-16) -142*a(n-17) -120*a(n-18) -92*a(n-19) -32*a(n-20) -4*a(n-22) for n>25
EXAMPLE
Some solutions for n=4
..1..1..0....1..0..0....0..1..1....0..3..0....0..1..1....0..1..1....1..1..0
..0..0..0....1..3..0....3..0..0....0..0..0....0..3..0....0..0..0....0..0..0
..0..3..1....0..0..1....0..0..0....0..0..3....0..0..0....3..0..1....0..0..0
..0..0..1....0..0..1....0..1..1....0..0..0....0..0..0....0..0..1....0..3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 15 2011
STATUS
approved