1,2

A 'zig-zag' walk does not contain 2 consecutive steps in the same direction.

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

a(4)=4 because of the following paths:

A._......A......A.._.......A_

...|_....|_.....|_|.|_......_|

.....|_....|_........_|....|_..._

.......|.....|_.....|_.......|_|.|

.......B.......B......B..........B

Cf. A034166.

Sequence in context: A002420 A112556 A054100 this_sequence A006181 A092635 A067920

Adjacent sequences: A034162 A034163 A034164 this_sequence A034166 A034167 A034168

nonn,walk

Felice Russo (felice.russo(AT)katamail.com)

a(7) to a(11) computed by David W. Wilson (davidwwilson(AT)comcast.net)