On Sat, 01 December 2001,

d.broadhurst@... wrote:

> I wrote:

>

> > Phil: As for "triplet middles": try the analyis mod 30.

>

> Phil used his fingers and toes

> (and perhaps some, but not enough, of Anna's):

>

> > Therefore the gamut of sums is

> > 30n + { 0, 4, 6, 8, 22, 24, 26, 28 }

>

> Err,

I do, don't I :-)

> what have you got against 2 mod 30, Phil?

> Example: take 13 from {11, 13, 17}

> and 19 from (17, 19, 23)

> to make 13 + 19 = 32 = 2 mod 30

I find fingers and toes far superior to programs like Mathematica, but just this once Mathematica is capable of doing this vast computational feet better than my own digits. How bizarre.

(sic, above, for reference)

In[24]:=

r30 = {11, 13, 17, 19}

Out[24]=

{11, 13, 17, 19}

In[25]:=

Union[Flatten[Outer[Mod[#1 + #2 , 30] &, r30, r30]]]

Out[25]=

{0, 2, 4, 6, 8, 22, 24, 26, 28}

Shall we just say it was an off day...

I'm glad that there's a post-processing filter which is able to extract some sense out of my gibberings. Ta muchly.

Phil

Don't be fooled, CRC Press are _not_ the good guys.

They've taken Wolfram's money - _don't_ give them yours.

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