OFFSET
1,2
COMMENTS
Column 3 of A203460
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
Robert Israel, Maple-assisted proof of formula
FORMULA
Empirical: a(n) = 18*a(n-1) -133*a(n-2) +640*a(n-3) -2309*a(n-4) +5762*a(n-5) -9918*a(n-6) +8864*a(n-7) +2970*a(n-8) -18151*a(n-9) +23183*a(n-10) +21799*a(n-11) -75109*a(n-12) +56329*a(n-13) -9892*a(n-14) -115814*a(n-15) +105665*a(n-16) +64162*a(n-17) -38348*a(n-18) +8767*a(n-19) +54790*a(n-20) -95246*a(n-21) -139155*a(n-22) +81259*a(n-23) +104482*a(n-24) +18968*a(n-25) -2909*a(n-26) -41630*a(n-27) -37578*a(n-28) +6670*a(n-29) +17693*a(n-30) +5629*a(n-31) -713*a(n-32) -928*a(n-33) -300*a(n-34) -52*a(n-35) -4*a(n-36).
Empirical formula verified (see link). - Robert Israel, Jun 27 2018
EXAMPLE
Some solutions for n=5
..1..1..0....0..0..0....2..2..2....0..1..1....1..1..0....0..2..2....0..2..2
..1..1..0....0..1..1....2..1..2....2..2..1....1..1..0....2..2..2....2..2..2
..1..1..1....0..1..1....2..1..2....2..2..1....0..0..0....2..1..0....2..1..1
..0..2..2....2..2..0....2..2..2....2..2..1....1..1..1....2..2..1....2..2..1
..0..2..2....2..2..0....0..2..2....2..2..1....1..1..1....2..2..1....2..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 02 2012
STATUS
approved