OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 330*a(n-1) - 28773*a(n-2) + 255420*a(n-3) - 599076*a(n-4) for n>5.
Empirical g.f.: 42*x*(2 + 420*x - 4154*x^2 + 9795*x^3 + 1152*x^4) / (1 - 165*x + 774*x^2)^2. - Colin Barker, Jan 29 2019
EXAMPLE
Some solutions for n=2:
..0..3..1. .2..0..3. .2..1..4. .4..5..0. .5..3..4. .0..4..3. .3..6..4
..4..4..5. .3..6..1. .2..0..2. .3..3..1. .3..6..2. .2..4..4. .4..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 07 2016
STATUS
approved