[seqfan] Finite cubefree words

[Neil Sloane]

The number of binary cubefree words of length n is given in A028445.

Could one of our Maple experts kindly add an IsCubeFree
Maple program that would test if a list is cube-free?

(I wrote one but it is too simple-minded to include)

Second question.  Call a binary cubefree word S a dead-end
if both S0 and S1 contain cubes. Meaning S can't be extended
to a cubefree word of greater length.

The smallest dead-ends are 00100100 and its complement.

What is a(n) = number of dead-ends of length n?
It begins, I think (for n>=0)
0 0 0 0 0 0 0 0 2 ...

Can these words be characterized in some other way?