OFFSET
1,1
COMMENTS
Column 7 of A221623
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5040*a(n-1) -8349390*a(n-2) +5234439280*a(n-3) -936232732785*a(n-4) +51206316902496*a(n-5) -99624831647040*a(n-6) +49349521382400*a(n-7)
EXAMPLE
Some solutions for n=3
..1..4..2..3..5..6..7....1..4..2..3..5..6..7....1..4..2..3..5..6..7
..2..1..3..7..6..4..5....2..1..3..5..4..6..7....2..1..3..6..7..5..4
..3..6..5..7..2..1..4....2..1..3..5..7..4..6....6..2..5..4..3..7..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 21 2013
STATUS
approved