OFFSET
1,2
COMMENTS
Column 5 of A221419.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..71
FORMULA
Empirical: a(n) = 276*a(n-2) -14620*a(n-4) +318164*a(n-6) -3590954*a(n-8) +22802458*a(n-10) -81585322*a(n-12) +150123806*a(n-14) -95749783*a(n-16) -40860150*a(n-18) +7351166*a(n-20) +978022*a(n-22) -197190*a(n-24) +7072*a(n-26).
EXAMPLE
Some solutions for n=4
..2..0..2..0..0....2..0..0..2..0....0..2..2..0..0....2..2..0..2..0
..2..2..2..2..0....0..2..0..2..0....2..0..0..2..2....0..0..0..2..0
..0..2..0..2..0....2..2..2..0..0....2..0..0..2..0....2..0..2..0..2
..0..2..0..2..0....2..0..0..2..2....2..2..0..0..2....0..2..2..0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 15 2013
STATUS
approved