OFFSET
1,1
COMMENTS
Column 3 of A183892.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..62
FORMULA
Empirical (for n>=2): 4^(n+3) - (n+3)*2^(n+4) - 2/3*(7*n^3+51*n^2+125*n+108). - Vaclav Kotesovec, Nov 27 2012.
Conjectures from Colin Barker, Apr 05 2018: (Start)
G.f.: 2*x*(8 + 50*x - x^2 - 1488*x^3 + 4469*x^4 - 5336*x^5 + 2996*x^6 - 656*x^7) / ((1 - x)^4*(1 - 2*x)^2*(1 - 4*x)).
a(n) = 12*a(n-1) - 58*a(n-2) + 148*a(n-3) - 217*a(n-4) + 184*a(n-5) - 84*a(n-6) + 16*a(n-7) for n>8.
(End)
EXAMPLE
Some solutions for n=2:
..1....3....1....2....0....0....1....0....1....2....2....0....3....1....3....0
..1....0....0....3....1....2....0....2....3....3....3....3....3....1....0....1
..0....3....1....3....1....1....2....0....1....1....0....0....0....0....1....2
..2....2....2....1....3....1....1....1....2....0....1....3....2....3....3....3
..3....0....3....0....2....0....2....1....0....3....3....2....2....2....2....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 07 2011
STATUS
approved