-1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -

[N. J. A. Sloane]

Yes, I agree, it is missing from the OEIS

Ed, will you kindly submit it?

The reason it is hard to look up is that
my lookup program ignores signs.  This is for
historical reasons - originally the database
contained only absolute values of sequences.

However, an equivalent sequence IS in the database
- change -1's to 0's and you get A021913.

Superseeker would have found that, I believe.

If Superseeker sees a two-valued sequence, it transforms
it to 6 versions, one of which replaces the
two values with 0's and 1's respectively.
(see the help page for the other versions)

Neil Sloane