A003304 Number of figure 8's with 2n edges on the square lattice.

2, 8, 32, 144, 708, 3696, 20296, 115624, 676828, 4044744, 24565432

Offset: 2

Author

N. J. A. Sloane

Keywords

• nonn
• more

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
• S. G. Whittington and J. P. Valleau, Figure eights on the square lattice: enumeration and Monte Carlo estimation, J. Phys. A 3 (1970), 21-27.

Links

• Sean A. Irvine, Illustration of initial terms.

Extensions

a(9)-a(12) from Sean A. Irvine, Mar 20 2017