OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..31
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).
EXAMPLE
Some solutions for n=5:
0 4 0 1 0 2 0 3 0 4 1 3 1 3 1 3 1 4 1 3
4 3 4 0 4 1 4 2 4 3 3 0 3 0 3 0 3 1 3 0
0 4 0 1 0 2 0 3 0 4 0 2 0 2 0 2 0 3 0 2
4 3 4 0 4 1 4 2 4 3 3 0 3 0 3 0 3 1 3 0
0 4 0 1 0 2 0 3 0 4 1 3 1 3 1 3 1 4 1 3
4 3 4 0 4 1 4 2 4 3 4 1 4 1 4 1 4 2 4 1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2014
STATUS
approved