The sequence A001653
creigh at o2online.de
creigh at o2online.de
Tue Aug 31 11:02:10 CEST 2004
This is one of the first sequences found based upon 3-dim aspects
of "Floret's cube" http://www.crowdog.de -> The Floretions ->
bottom of page
Define x = .5(-'i + i' + 'ii' - 'jj' - 'kk' + 1)
In that picture " 'i " is represented by any one of the three tips
at the top of the "cube" [the object seems to comprise three "tilted
pyramids" ]. The other elements making up x, namely
i', 'ii', 'jj', 'kk', 1 are elements which are either directly on the pyramid
or (in the case of 'ii' and 1) symmetric to it. Writing " -'i " instead
of " 'i " in x further "emphasizes" (in a way I cannot describe exactly)
that 'i should be treated special (indeed, it is the tip of the pyramid)...
so should 'jj' and 'kk' because they are on the pyramid whilst 'ii' is
not.
We have ( ves( x^n ) ) = (0, -1, -2, -3, -4, -5, -6, -7, -8, )
Nothing spectacular about that sequence in itself...
unless if the number of multiplications involved
( = 36 for each n after simplifying ) is taken into account;
this results in a kind of "silent beauty".
Now, I define y = .5( 'i - i' + 'ii' - 'jj' - 'kk' + 1). By doing so, we
are
adding even more "symmetry" to the problem because there is actually
no reason to favor 'i over i' when setting up the cube. Of course,
( ves( y^n) ) = (0, -1, -2, -3, -4, -5, -6, -7, -8, ...) also.
We have xy = (3/2)'ii' - 'jj' - 'kk' - 'jk' + 'kj' + (3/2)1
and ves ( (xy)^n ) = (1, 5, 29, 169, 985, ...)
which is
http://www.research.att.com/projects/OEIS?Anum=A001653
Sincerely,
Creighton
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