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A268950
Number of perfectly looping walks containing n pieces from the set described in the links.
0
0, 0, 0, 2, 1, 5, 7, 33, 74, 304, 986
OFFSET
1,4
COMMENTS
These perfectly looping walks are similar, but still different from self-avoiding polygons on the square lattice (A002931) and allow one to realize toy tracks.
Rotations, reflections and translations are allowed.
EXAMPLE
Some examples are given in the linked paper arxiv.org:1603.08775:
* the a(7)=7 tracks are plotted in Figure 14, p. 24
* some of a(8)=33 tracks are plotted in Figure 15, p. 25
* some of a(9)=74 tracks are plotted in Figure 16, p. 26
CROSSREFS
Cf. A002931.
Sequence in context: A193662 A279508 A175770 * A141507 A193603 A059274
KEYWORD
nonn,more
AUTHOR
Jérôme Bastien, Apr 25 2016
STATUS
approved