[seqfan] (a+b) divides the concatenation [a,b]

Eric Angelini Eric.Angelini at kntv.be
Tue Sep 21 10:40:57 CEST 2010

Hello SeqFans,
this is nice too (?):

U = 1,2,4,5,10,12,15,18,36,45,...

U is monotonically increasing
a(n+1) is the smallest integer > a(n)
such that [a(n)+a(n+1)] divides the
concatenation [a(n),a(n+1)]

Example here:

1+2 divides 12
2+4 divides 24
4+5 divides 45
5+10 divides 510

Dropping the monotonically increasing
constraint would give V -- which I haven't
looked at yet.


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