editing

approved

R. H. Hardin, <a href="/A220591/b220591.txt">Table of n, a(n) for n = 1..210</a>

allocated for R. H. Hardin

Number of ways to reciprocally link elements of an nX3 array either to themselves or to exactly two king-move neighbors

1, 33, 423, 6156, 87542, 1250507, 17847210, 254759570, 3636434730, 51906768670, 740920520709, 10575949381405, 150961805783944, 2154838890134463, 30758314061665953, 439046226888854973, 6266975132151978539

1,2

Column 3 of A220595

Empirical: a(n) = 11*a(n-1) +46*a(n-2) +14*a(n-3) -46*a(n-4) -63*a(n-5) +35*a(n-6) +20*a(n-7) +a(n-8) -4*a(n-9) -a(n-10)

Some solutions for n=3 0=self 1=nw 2=n 3=ne 4=w 6=e 7=sw 8=s 9=se (reciprocal directions total 10)

.00.67.48...69.47.00...00.68.48...00.79.00...89.78.00...00.00.78...68.46.48

.38.89.28...38.18.00...00.29.28...39.68.14...23.12.00...00.37.27...28.79.28

.26.24.12...26.24.00...00.00.12...00.12.00...00.00.00...36.34.00...23.00.12

allocated

nonn

R. H. Hardin Dec 16 2012

approved

editing

allocated for R. H. Hardin

allocated

approved