# [seqfan] Re: A036322

Wed Jun 25 20:45:19 CEST 2014

```*Prime* factors. The prime factors of 6 are 2 and 3.

-----Original Message-----
From: Harvey P. Dale <hpd at hpdale.org>
To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
Sent: Wed, Jun 25, 2014 1:31 pm
Subject: [seqfan] A036322

There is something I don't understand about the above sequence.
According to
the definition, the prime factors of its terms can have digits of
either 6 or 7.
But the first term is 49, i.e., 7*7, rather than 36, i.e., 6*6.  And 42
is also
missing, i.e., 6*7.  For the first 50 terms of the sequence, I get the
following
(which is drastically different than what is provided in the current
OEIS
version): 36, 42, 49, 216, 252, 294, 343, 396, 402, 456, 462, 469, 532,
539,
1296, 1512, 1764, 2058, 2376, 2401, 2412, 2736, 2772, 2814, 3192, 3234,
3283,
3724, 3773, 3996, 4002, 4056, 4062, 4356, 4422, 4489, 4596, 4602, 4656,
4662,
4669, 4732, 4739, 5016, 5082, 5092, 5159, 5362, 5369, 5432.  I used the
following Mma program to generate these terms:
With[{ss=Flatten[Table[FromDigits/@Tuples[{6,7},n],{n,4}]]},Take[Union[Fl
atten[Table[Times@@@Tuples[ss,n],{n,2,4}]]],90]]
Am I misunderstanding something?
Best,
Harvey

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