___Rather than continue this in the Katabatak thread where it is slightly off topic now, I decided to carry on here.
____Eureka! A little epiphany. The problem at hand is in regard to this Fuller drawing:
http://www.rwgrayprojects.com/synerg...igs/f9001.html
___Observing on the drawing the lower right hand quadrant & the stacking of tetrahedrons that form powers of 3. Although the geometry is clearly a proof to me that no two powers of three sum to a power of three, I expressed a desire for a formula for deriving the number of tetrahedrons in each successive layer, i.e. a formula where n is the layer number (frequency in close-packing terms) & the result is how many tetrahedrons in that layer. Fuller gives the starting as 1, 7, 19, 37... I noted they differed by multiples of 6 & the question is which multiples. The first is 1 [1*6], the second is 3 [3*6], then 6, then 10 & so on. Does the se {1,3,6,10...} look familiar?
___It is the set of triangular numbers! So now I have my formula; it is the formula for triangular number, times 6, plus 1.
___Therfore, for n = the layer, the number of close-packed tetrahedrons is
(n/2 * (n+1)) * 6 + 1
___Anyway, it's the middle of the night here & I jumped up from near sleep to post this; I intend to take it up again.

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semantics is not always just pedantic quibbling. ~ douglas r. hofstadter