OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 15*a(n-2) - 15*a(n-3) - 80*a(n-4) + 80*a(n-5) + 180*a(n-6) - 180*a(n-7) - 144*a(n-8) + 144*a(n-9).
Empirical g.f.: 4*x*(52 + 43*x - 717*x^2 - 483*x^3 + 3481*x^4 + 1698*x^5 - 7062*x^6 - 1872*x^7 + 5040*x^8) / ((1 - x)*(1 - 2*x)*(1 + 2*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Oct 18 2018
EXAMPLE
Some solutions for n=4:
3 0 2 0 4 2 4 2 3 0 3 0 4 2 4 2 4 0 4 2
1 3 0 3 0 3 0 3 0 2 0 2 1 4 1 4 1 2 1 4
4 1 3 1 2 0 2 0 3 0 3 0 3 1 3 1 4 0 4 2
1 3 0 3 1 4 1 4 0 2 0 2 0 3 0 3 0 1 0 3
3 0 2 0 2 0 2 0 4 1 4 1 2 0 2 0 4 0 4 2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2014
STATUS
approved