[seqfan] Re: A002046 Larger of amicable pair

Christopher Gribble chris.eveswell at virgin.net
Mon Apr 12 19:39:07 CEST 2010

Hi Michael,

Note that A002025 and A002046 are the left and right hand columns of your
table respectively so that each pair of amicable numbers have corresponding
list positions.  This is a good reason not to reorder A002046.

Best regards,

Chris Gribble

-----Original Message-----
From: seqfan-bounces at list.seqfan.eu [mailto:seqfan-bounces at list.seqfan.eu]
On Behalf Of Michael Porter
Sent: 12 April 2010 5:35 PM
To: Sequence Fanatics Discussion list
Subject: [seqfan] A002046 Larger of amicable pair

This sequence is sorted according to the smaller of the amicable pair, which
puts 76084, 123152, 202444, etc. out of numerical order.  Should this
sequence be put in numerical order?

Amicable pairs are pairs of positive integers (n,m) such that the sum of
proper divisors of n is m and the sum of proper divisors of m is n.  Here
are the amicable pairs under 10^5:

220 284
1184 1210
2620 2924
5020 5564
6232 6368
10744 10856
12285 14595
17296 18416
63020 76084
66928 66992
67095 71145
69615 87633
79750 88730

- Michael


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