OFFSET
1,1
COMMENTS
Column 2 of A226340.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..144
FORMULA
Conjectures from Colin Barker, Mar 16 2018: (Start)
G.f.: x*(2 + 12*x + 5*x^2 + 20*x^3 + 13*x^4 + 2*x^5 + 12*x^6 - 2*x^7 + x^9 - 2*x^10 - x^11 + x^12) / ((1 - x)^5*(1 + x)^4*(1 + x^2)^2).
a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) + a(n-4) - a(n-5) - 4*a(n-6) + 4*a(n-7) + a(n-8) - a(n-9) + 2*a(n-10) - 2*a(n-11) - a(n-12) + a(n-13) for n>13.
(End)
EXAMPLE
Some solutions for n=3:
.-1...-1...-1....0...-1...-2...-1...-2....1....1...-2...-1...-1...-1....1...-2
..1...-1....2....1....1...-1...-1...-1....1....2...-2....0...-1....0....1....1
..2....1....2....1....1....0....0....1....2....2....1....1....2....2....1....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 04 2013
STATUS
approved