OFFSET
1,1
COMMENTS
Column 6 of A220562
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 43*a(n-1) -317*a(n-2) +783*a(n-3) -721*a(n-4) +375*a(n-5) -125*a(n-6) +19*a(n-7) -a(n-8) for n>9
EXAMPLE
Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)
..0..7..6..4..0..0....6..4..6..4..6..4....0..0..0..7..0..0....0..0..0..7..0..7
..3..0..7..0..6..4....0..0..0..0..7..0....0..7..3..7..6..4....6..4..3..0..3..0
..0..3..0..6..4..0....6..4..0..3..0..0....3..0..3..0..6..4....0..0..0..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 16 2012
STATUS
approved