OFFSET
1,1
COMMENTS
Column 2 of A219173.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/8)*n^4 - (3/4)*n^3 + (55/8)*n^2 - (49/4)*n + 8 for n>1.
Conjectures from Colin Barker, Mar 11 2018: (Start)
G.f.: x*(3 - 8*x + 18*x^2 - 22*x^3 + 13*x^4 - x^5) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>6.
(End)
EXAMPLE
Some solutions for n=3:
..1..1....0..0....0..0....1..0....1..1....0..0....1..1....2..2....0..0....1..1
..1..1....0..0....0..0....0..0....1..1....0..0....1..1....2..2....0..1....1..1
..2..1....2..2....2..0....2..0....1..2....1..2....1..1....2..2....2..1....2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 13 2012
STATUS
approved