OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 62*a(n-1) - 1031*a(n-2) + 2180*a(n-3) - 1535*a(n-4) + 350*a(n-5) - 25*a(n-6) for n>7.
Empirical g.f.: 12*x*(18 - 315*x + 2265*x^2 - 8158*x^3 + 10756*x^4 - 4951*x^5 + 897*x^6) / ((1 - x)^2*(1 - 30*x + 5*x^2)^2). - Colin Barker, Jan 20 2019
EXAMPLE
Some solutions for n=2:
..1..0..0..1. .1..3..1..2. .3..1..0..1. .0..2..2..2. .1..0..1..3
..0..1..1..3. .2..3..2..3. .0..1..3..2. .3..2..3..0. .1..1..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 20 2016
STATUS
approved