[seqfan] Re: correlation A161918 and A030229

[franktaw at netscape.net]

OK.  Now is there anything in A161918, other than 8, that is not in 
A006881?

(Clearly there isn't.)

Franklin T. Adams-Watters


-----Original Message-----
From: Maximilian Hasler <maximilian.hasler at gmail.com>

A161918 should say "(counted with multiplicity)" :

(PARI)
isA161918(n)={ n+1 == sigma(n)-(n=factor(n))[,1]~*n[,2] }

? for(n=1,500, isA161918(n)&print1(n","))
6,8,10,14,15,21,22,26,33,34,35,38,39,46,51,55,57,58,62,65,69,74,77,82,85,
86,87,91,
93,94,95,106,111,115,118,119,122,123,129,133,134,141,142,143,145,146,155,
158,
159,161,166,177,178,183,185,187,194,201,202,203,205,206,209,213,214,215,2
17,218
...


From: Benoit Jubin:
It seems that A161918 is an incorrect version of A006881. This is
pretty easy to see when writing down the prime factorization.  And
these are a (small) subset of A030229.

Benoit