Unknown terms

[Antti Karttunen]

Ed Pegg wrote:
> 
> How should sequences with unknown terms be entered?

I would use here zero, because it doesn't make a sense as a factor.
(And leave 1 for primes).

But see Neil's mail about the topic.

> 
> Smallest nontrivial prime factors of Googleplex + n
>  ?, ?, 7, 1129, 29, ?, 53, ?, 5501, 7,
> 59, 1327, ?, 61, 211, 17, 7, ?, 43, 389,
> 173, ?, 13, 7, 18797, 31, 37, 8297, 19, 13879
> 
> (Here, I define trivial prime factors as 2, 3, 5, and 11 -- those with easy
> primality tests.)

I think the definition of triviality is too arbitrary here.

I remember that "The Penguin dictionary of curious and interesting
numbers", by Dawid Wells 1986 (reprinted 1988. ISBN 0-14-008029-5)
lists easy primality testing algorithms for many other
numbers (also primes?) as well.


BTW, I remember, from the times before www.google.com,
that the spelling was "Googol" and "Googolplex", but maybe they
are finnicized variants (from the Guinness book of records,
probably?), or I'm mixing this with the name of Helsinki book
store called "Gogol's nose" (after Nikolai Gogol, of course).


Terveisin,

Antti Karttunen


> 
> --Ed Pegg Jr.