[seqfan] Counting Problem

[Harvey P. Dale]

David:

 

            Is the answer always 1?  The numbers satisfying your
conditions, starting with n=1, are 5, 75, 375, 9375, 59375, 359375, and
3359375.  Note that once any such number is found, the number for the
next higher n has the same ending digits with a prepended different odd
digit.

 

            Best,

 

            Harvey

 

-----Original Message-----

From: seqfan-bounces at list.seqfan.eu
[mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of David Wilson

Sent: Tuesday, June 16, 2009 11:22 PM

To: Sequence Fans

Subject: [seqfan] Counting problem

 

How many n-digit numbers with all odd digits are divisible by 5^n?