OFFSET
1,2
COMMENTS
Column 7 of A220632
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 11*a(n-1) +119*a(n-2) +510*a(n-3) +1074*a(n-4) +735*a(n-5) -1120*a(n-6) -2716*a(n-7) +5687*a(n-8) -4250*a(n-9) +1973*a(n-10) -802*a(n-11) +244*a(n-12) -36*a(n-13) -4*a(n-14)
EXAMPLE
Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)
.00.00.00.00.00.67.47...00.67.47.67.47.67.47...00.67.46.47.00.67.47
.00.00.00.00.37.36.47...36.34.37.37.36.34.00...36.46.34.00.37.37.00
.00.00.00.36.46.34.00...00.36.34.00.00.00.00...00.00.00.36.34.00.00
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 17 2012
STATUS
approved