A220566 Number of ways to reciprocally link elements of an 5Xn array either to themselves or to exactly one horizontal or antidiagonal neighbor.

1, 89, 1332, 36640, 810778, 19333688, 449429440, 10536960271, 246344047375, 5764617097479, 134855487893714, 3155067573838299, 73813420827751321, 1726896241431387347, 40401344327635974032, 945204561717125804080

Offset: 1

Author

R. H. Hardin Dec 16 2012

Keywords

• nonn

Comments

Row 5 of A220562

Examples

			Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)
..0..0..0....6..4..0....6..4..7....0..0..0....0..6..4....6..4..0....0..0..7
..0..0..0....0..0..0....0..3..0....0..6..4....6..4..7....6..4..0....0..3..0
..0..0..7....6..4..0....0..0..0....0..0..0....0..3..0....0..0..0....0..0..7
..0..3..0....6..4..0....6..4..7....6..4..0....0..0..0....0..7..0....0..3..0
..0..0..0....6..4..0....0..3..0....6..4..0....0..0..0....3..0..0....0..6..4
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 8*a(n-1) +332*a(n-2) +1166*a(n-3) -10416*a(n-4) -41922*a(n-5) +174048*a(n-6) +535206*a(n-7) -1872086*a(n-8) -2804534*a(n-9) [phone]*a(n-10) +3617576*a(n-11) -32706416*a(n-12) +4049368*a(n-13) [phone]*a(n-14) -14992866*a(n-15) -49988407*a(n-16) [phone]*a(n-17) [phone]*a(n-18) -9212528*a(n-19) -13108544*a(n-20) +2853616*a(n-21) +3512372*a(n-22) -487178*a(n-23) -584214*a(n-24) +44610*a(n-25) +58000*a(n-26) -2006*a(n-27) -3248*a(n-28) +34*a(n-29) +92*a(n-30) -a(n-32)