OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 37*a(n-1) - 342*a(n-2) + 936*a(n-3) - 1296*a(n-4).
Empirical g.f.: x*(1 - 6*x)*(43 - 120*x + 216*x^2) / (1 - 37*x + 342*x^2 - 936*x^3 + 1296*x^4). - Colin Barker, Sep 15 2018
EXAMPLE
Some solutions for n=2:
..6..6....3..2....4..0....6..5....6..3....3..5....2..0....5..3....3..1....4..3
..5..6....1..5....3..1....4..3....5..2....5..6....3..2....1..4....0..1....5..5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 23 2013
STATUS
approved