OFFSET
1,1
COMMENTS
Column 7 of A204642.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..121
FORMULA
Empirical: a(n) = 5*a(n-1) -3*a(n-2) -4*a(n-3) -12*a(n-4) +12*a(n-5) +21*a(n-6) -9*a(n-7) -9*a(n-8) for n>10.
Empirical g.f.: x*(144255 - 713135*x + 401815*x^2 + 560869*x^3 + 1761457*x^4 - 1601082*x^5 - 3013092*x^6 + 1151934*x^7 + 1230813*x^8 + 1476*x^9) / ((1 - x)*(1 - x - x^2)*(1 - 3*x - 3*x^2)*(1 - 3*x^3)). - _Colin Barker_, Jun 08 2018
EXAMPLE
Some solutions for n=3:
..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1
..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1
..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1
..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1
..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
_R. H. Hardin_, Jan 17 2012
STATUS
approved