login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A233260
Number of 5Xn 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabeled 6-colorings with no clashing color pairs).
1
236, 32896, 10620928, 3439984640, 1159192379392, 393427728465920, 134179300927602688, 45829217084770353152, 15662712220567239393280, 5353914504847465071509504, 1830206096861520940880625664
OFFSET
1,1
COMMENTS
Row 5 of A233256
LINKS
FORMULA
Empirical: a(n) = 512*a(n-1) -65536*a(n-2) +2490368*a(n-3) +17825792*a(n-4) -2818572288*a(n-5) +51539607552*a(n-6) -274877906944*a(n-7) for n>11
EXAMPLE
Some solutions for n=2
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..2..5....2..5....2..0....0..1....2..0....0..2....0..2....2..5....2..1....5..4
..2..0....3..1....1..3....0..2....4..3....4..5....5..3....4..3....0..2....2..1
..4..0....5..3....1..3....4..3....5..2....2..4....1..0....1..5....0..2....3..4
..3..5....4..5....4..5....5..3....0..2....0..1....2..4....3..0....0..2....5..3
CROSSREFS
Sequence in context: A220760 A218179 A005391 * A218520 A233243 A233200
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 06 2013
STATUS
approved