OFFSET
1,1
COMMENTS
Column 2 of A219217.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..185
FORMULA
Empirical: a(n) = (1/24)*n^4 - (5/12)*n^3 + (59/24)*n^2 - (37/12)*n + 1 for n>3.
Conjectures from Colin Barker, Mar 11 2018: (Start)
G.f.: x*(3 - 12*x + 22*x^2 - 23*x^3 + 16*x^4 - 8*x^5 + 4*x^6 - x^7) / (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
All solutions for n=3:
..0..0....1..1....2..2....1..1....1..1....0..0....0..0
..0..0....1..1....2..2....0..0....1..1....0..0....0..0
..2..2....2..2....2..2....0..0....1..1....1..1....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 14 2012
STATUS
approved