OFFSET
1,1
COMMENTS
Column 2 of A223071.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..41
FORMULA
Empirical: a(n) = 16*a(n-1) -106*a(n-2) +376*a(n-3) -769*a(n-4) +904*a(n-5) -564*a(n-6) +144*a(n-7).
Empirical g.f.: x*(16 - 106*x + 376*x^2 - 769*x^3 + 904*x^4 - 564*x^5 + 144*x^6) / ((1 - x)^2*(1 - 2*x)^2*(1 - 3*x)^2*(1 - 4*x)). - Colin Barker, Feb 18 2018
EXAMPLE
Some solutions for n=3:
..2..1....2..2....3..1....3..3....2..0....2..2....3..0....3..2....1..1....2..0
..1..2....2..2....2..2....3..3....2..1....2..2....3..2....3..2....2..3....3..2
..0..2....2..2....0..2....0..3....3..2....3..3....0..3....0..0....0..1....1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin; Mar 14 2013
STATUS
approved