OFFSET
1,1
COMMENTS
Column 3 of A183622.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 21*a(n-1) - 84*a(n-2) - 112*a(n-3) + 192*a(n-4).
Empirical g.f.: 4*x*(9 - 57*x - 68*x^2 + 128*x^3) / ((1 - 5*x - 12*x^2)*(1 - 16*x + 16*x^2)). - Colin Barker, Mar 30 2018
EXAMPLE
Some solutions with the first square being 0123 for 3 X 4:
0 1 2 1 0 1 0 4 0 1 0 1 0 1 0 1 0 1 0 3
2 3 0 4 2 3 2 3 2 3 2 3 2 3 2 4 2 3 2 4
1 4 1 2 0 4 1 4 1 0 1 0 4 0 1 0 0 4 0 3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2011
STATUS
approved