[seqfan] Re: A045655

Ed Jeffery lejeffery7 at gmail.com
Sun Jan 1 06:18:36 CET 2012


It seems as if Geoffrey Critzer contradicted your definition in your title
for A045655 by dropping your reference to "reversed complement." The
question is, what do you mean by that terminology: are you referring to
"ones complement" from binary arithmetic? If so, then for longer strings
the symmetry you seem to be suggesting will be lost.

If you are referring to dihedral symmetry, then, as you know, two objects
in the plane are either (or they are not) congruent up to rotations or they
are (or are not) reflections in a line. So, in terms of sequences of digits:

Are you ordered pairs (a,b) supposed to be such that either (i) a equals b,
or (ii) b is a reflection of a (i.e., b takes the digits of a in reverse
order)? If so, then evidently Geoffrey Critzer's definition must be the
correct one.

It is a bit confusing, but I like your sequence.


Ed Jeffery

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