OFFSET
1,2
COMMENTS
A 'zig-zag' walk does not contain 2 consecutive steps in the same direction.
LINKS
Eric Weisstein's World of Mathematics, Self-avoiding walk.
EXAMPLE
a(4)=4 because of the following paths:
A._......A......A.._.......A_
...|_....|_.....|_|.|_......_|
.....|_....|_........_|....|_..._
.......|.....|_.....|_.......|_|.|
.......B.......B......B..........B
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
EXTENSIONS
a(7)-a(11) computed by David W. Wilson
a(12)-a(13) computed by Luca Petrone, Dec 31 2015
a(14)-a(20) from Andrew Howroyd, Jan 15 2018
STATUS
approved