[seqfan] Re: extending A179192 (periods of 1/n)

Douglas McNeil mcneil at hku.hk
Fri Nov 19 01:06:42 CET 2010

> A179192 ( n: gcd(n,10) >1 and the period of 1/n in decimal representation a prime)

(1) Terminology question: isn't it a little awkward to use period not
for the length of what's repeated but for the content of what's
repeated?  I would've called this the repetend, but that term is
almost completely absent from the OEIS: it's only mentioned once in

Some sequences use "period" the way I'd expect: e.g. A002371, A007732,
A007138, and A051626, and use "periodic part" (A036275) for repetend.
But there are references which show that people might have been using
"period" to refer to the repetend for a long time, and many other OEIS
sequences do as well, so it seems to have a history behind it.

Am I unexpectedly quirky?

(2) Base for these sequences: yea or nay?   Many are written in
"base-avoiding" phrasing.


Department of Earth Sciences
University of Hong Kong

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