Question on offsets (tetrahedral numbers)

[Joshua Zucker]

Speaking of offsets and such:
I agree that there are a lot that ought to be corrected, and some that
are used inconsistently within the comments/formulas for the seq.  So
a lot of other cleaning up (of those formulas/comments) might be
necessary when we start being more careful about offsets.

I had a very tough time deciding what to do with some "farey fraction"
sequences:
They start 0/1, 1/0, ...

And sometimes the ... part was already in the OEIS as numerators or
denominators or both.

I had to decide whether to stick the 0,1 or 1,0 in front and make a
new seq cross-ref to the existing one, or just to comment on the
existing seq about the Farey fraction connection.

There's also the issue about whether it's OK to have a "frac" sequence
of denominators that includes zero!

Any opinions on this one?  (For the record, in a couple of the "most
important" cases, relating to e and pi and the golden ratio and maybe
sqrt(2), I made new seq with the 0 and 1 in front, but for any others
I come across I will just stick in a comment about the Farey
connection.)

--Joshua Zucker