OFFSET
1,2
COMMENTS
Column 3 of A194893.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..24
FORMULA
Empirical (for n>=3): 9*2^(2*n-2) - (1-(-1)^n)*21/8*2^(3*n/2+1/2) - (1+(-1)^n)*15/4*2^(3*n/2) + 6*2^n. - Vaclav Kotesovec, Nov 27 2012
Empirical g.f.: x*(1 - 3*x + 6*x^2 + 96*x^3 + 80*x^4 - 192*x^5) / ((1 - 2*x)*(1 - 4*x)*(1 - 8*x^2)). - Colin Barker, May 05 2018
EXAMPLE
Some solutions for 4 X 4:
0 0 0 0 0 0 0 0
0 1 1 2 1 1 1 2 1 2 1 2 1 2 0 1
2 2 3 3 3 0 2 2 3 1 3 3 1 2 3 1 0 0 3 3 0 2 1 0
1 0 3 1 0 1 2 2 3 0 1 2 2 0 1 1 3 0 0 2 2 3 1 2 2 1 0 3 2 3 0 1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 04 2011
STATUS
approved