OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/4)*n^4 - (1/3)*n^3 + (13/4)*n^2 + (11/6)*n + 7.
Conjectures from Colin Barker, Sep 17 2018: (Start)
G.f.: x*(12 - 35*x + 48*x^2 - 26*x^3 + 7*x^4) / (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>5.
(End)
EXAMPLE
Some solutions for n=4:
..0..0..0..2....0..0..0..2....0..0..0..2....0..2..2..2....0..0..0..0
..1..1..1..0....1..1..1..0....1..1..1..0....1..0..2..2....1..1..1..1
..2..2..2..1....1..1..1..0....1..1..1..1....1..0..2..2....2..2..2..2
..2..2..2..2....2..2..2..1....2..2..2..1....2..1..0..2....2..2..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 23 2013
STATUS
approved