OFFSET
1,1
COMMENTS
Column 4 of A189814.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 20*n^2 + 228*n - 930 for n>15.
Conjectures from Colin Barker, May 03 2018: (Start)
G.f.: 2*x*(23 + 10*x + 3*x^2 - x^3 + 3*x^4 - 12*x^5 + 6*x^6 - 7*x^7 - x^8 + 2*x^9 - 6*x^10 + 4*x^12 - 4*x^13 + 2*x^16 - 2*x^17) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>11.
(End)
EXAMPLE
Some solutions for n=3:
..1..4....3..3....3..3....3..3....1..2....2..0....3..2....0..3....3..2....0..1
..0..4....0..3....1..3....1..1....2..1....0..1....0..2....0..2....2..2....0..0
..1..0....3..4....3..0....2..4....3..4....3..2....3..3....1..3....3..3....3..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 28 2011
STATUS
approved