[seqfan] Re: Knife numbers

Frank Adams-Watters franktaw at netscape.net
Sat Sep 20 23:36:10 CEST 2014


You have to specify that you can't cut before a zero. Otherwise, e.g., 
101 would be included.

This suggests that you should omit 10, 20, 30, ,,, Allowing them makes 
the definition more complex. And having every multiple of 10 be in the 
sequence is not very interesting.

Note that by the definition you are using, 100, divisible by 10 + 0, 
should be in the sequence.

Franklin T. Adams-Watters

-----Original Message-----
From: Eric Angelini <Eric.Angelini at kntv.be>
To: Sequence Discussion list <seqfan at list.seqfan.eu>
Sent: Sat, Sep 20, 2014 3:58 pm
Subject: [seqfan] Knife numbers



Hello SeqFans,
If I'm not wrong, the "Knife numbers"
(as we might call them) are not in the
database.

A "knife number" K can be divided
in two chunks P and Q such that P+Q
divide K.

K = 10, 12, 18, 20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50, 54, 60, 63, 
70, 72,
80, 81, 84, 90, 105, 108, 110, 120, 126, 130, 132,...

Examples:
12 is divisible by 1+2 (result = 4)
126 is divisible by 12+6 (result = 7)
132 is divisible by 1+32 (result = 4)
...
Best,
É.


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