OFFSET
1,1
COMMENTS
Column 1 of A253524.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 8*a(n-1) - 15*a(n-2) - 12*a(n-3) + 44*a(n-4) - 8*a(n-5) - 16*a(n-6) for n>13.
Empirical g.f.: x*(81 - 178*x - 365*x^2 + 205*x^3 + 461*x^4 + 1514*x^5 + 1780*x^6 - 190*x^7 - 1648*x^8 - 1440*x^9 - 720*x^10 - 224*x^11 - 32*x^12) / ((1 - x)*(1 - 2*x)*(1 - 5*x - 2*x^2 + 16*x^3 + 8*x^4)). - Colin Barker, Mar 20 2018
EXAMPLE
Some solutions for n=4:
..2..1....2..2....0..1....0..0....1..1....0..2....2..2....1..1....1..2....2..0
..2..1....2..0....1..1....2..2....2..1....1..0....2..1....2..2....0..1....2..2
..2..0....2..1....1..1....0..0....2..0....2..1....2..0....2..2....0..0....2..2
..1..1....1..1....0..1....0..0....1..0....0..1....2..2....0..2....1..0....2..1
..1..2....1..2....1..2....1..2....1..2....1..2....0..1....1..2....2..0....2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2015
STATUS
approved