OFFSET
1,1
COMMENTS
Column 2 of A219595.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/12)*n^4 - (1/3)*n^3 + (47/12)*n^2 - (14/3)*n + 2 for n>1.
Conjectures from Colin Barker, Mar 12 2018: (Start)
G.f.: x*(3 - 8*x + 16*x^2 - 19*x^3 + 12*x^4 - 2*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:
..0..0....0..0....0..0....1..0....0..0....1..1....0..0....2..2....1..0....0..0
..1..0....2..0....0..0....0..0....1..0....1..1....0..0....2..2....0..0....0..0
..1..1....2..2....1..1....1..0....0..0....2..1....2..0....2..2....2..0....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 23 2012
STATUS
approved