OFFSET
1,2
COMMENTS
Column 5 of A220725
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 24*a(n-1) +104*a(n-2) +571*a(n-3) +3582*a(n-4) +7794*a(n-5) +4788*a(n-6) -16926*a(n-7) -90288*a(n-8) -168845*a(n-9) -84443*a(n-10) +109179*a(n-11) +193126*a(n-12) +248993*a(n-13) +425415*a(n-14) +384428*a(n-15) +353459*a(n-16) +31964*a(n-17) -136170*a(n-18) -85703*a(n-19) -29195*a(n-20) +14155*a(n-21) +6903*a(n-22) +243*a(n-23) -252*a(n-24) -25*a(n-25)
EXAMPLE
Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)
.69.47.69.46.47...69.47.00.69.47...00.69.46.46.47...00.69.46.49.00
.39.19.00.13.00...39.16.47.36.14...00.69.14.37.00...00.00.16.46.14
.00.16.14.00.00...00.13.00.00.00...00.00.13.00.00...00.00.00.00.00
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 18 2012
STATUS
approved