[seqfan] Mystery: trios in A046346.
israel at math.ubc.ca
israel at math.ubc.ca
Tue Jul 23 03:32:51 CEST 2019
A046346 is "Composite numbers that are divisible by the sum of their prime
factors (counted with multiplicity)".
Noticing that there are pairs x,x+2 both in A046346, J.M. Bergot and I
jointly submitted A309310, which is "Intersection of A046346 and
(A046346-2)". I noticed that A046346 also contained a trio x,x+2,x+4,
namely 646, 648, 650, which I thought to be an interesting coincidence.
Well, just now I was constructing a b-file for A309310: not so easy because
the numbers get quite sparse. To get A309310(200) I had to go all the way
up to 192678462. Thus it seems to me astonishing that there's another trio:
38104990, 38104992, and 38104994 are all members of A046346.
Can anyone make sense of this? Are there more trios? Infinitely many?
Cheers,
Robert
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