# a puzzle sequence

Graeme McRae g_m at mcraefamily.com
Fri Jul 29 22:52:31 CEST 2005

```Has anyone had any luck with this one?  I posted this question on a math
board I frequent (nrich.maths.org) but so far the only comments have been
that the numbers alternate between two-digit and three-digit, and that they
are a pair of primes followed by a pair of non-primes, and continuing to
alternate in that fashion.  I googled for "87   711   43   269   65   555
39   421   17" and saw someone asked the question back in February, on the
FreeMathHelp.com message board, as follows:

ritanyc
Full Member
Joined: 28 Dec 2004
Posts: 109
Location: New York City
Posted: Wed Feb 23, 2005 11:47 am    Post subject: Pattern
--------------------------------------------------------------------------------
87, 711, 43, 269, 65, 555, 39, 421, 17,.......
What are the next 5 numbers?
_________________
Rita
--------------------------------------------------------------------------------

Denis
Senior Member
Joined: 17 Feb 2004
Posts: 844
Location: Ottawa, Ontario
Posted: Wed Feb 23, 2005 11:37 pm    Post subject:
--------------------------------------------------------------------------------
s'that supposed to be mathematical, or alpha related,
or just a plain old puzzle?
_________________
I'm just an imagination of your figment!
--------------------------------------------------------------------------------

But then there was no follow-up with answers to Denis' questions or an
knows if there are many ritas in nyc?  I bet there are.  In any case, I sent
I'll let you know if anything turns up.  In the mean time, has anyone else

--Graeme

----- Original Message -----
From: "N. J. A. Sloane" <njas at research.att.com>
To: <seqfan at ext.jussieu.fr>
Sent: Tuesday, July 26, 2005 5:49 AM
Subject: a puzzle sequence

>
> SeqFans,  this just came in. Can anyone solve it?
> I don't know the answer.  NJAS
>
>
>> need help with a math thing
>>
>>
>> 87   711   43   269   65   555   39   421   17   ___    ___    ___
>>
>> What are three numbers?  What is the pattern?  What do they have in
>> common?
>>
>> If you could help it would be great!!
>
>
>

```