[seqfan] Re: A245486

[israel at math.ubc.ca]

OK, that's finite. Looks big, but log[2]( 9591468737351909376) < 64
and log[3](9591468737351909376) < 40, so
we only need to consider 2^a*3^b (+-) 1 with a <= 63 and b <= 40. 
Since we know we must have b == 28*a mod 44, that gives us only 63
cases to try; none of them work, so we conclude that 3*89 does not
occur!

Cheers,
Robert Israel

On Jul 24 2014, Don Reble wrote:

>>> Are there any odd members of A006881 that do not occur in the sequence?
>
>> A candidate would be 3*89 = 267. ...
>> But it's not obvious to me how to make this search finite.
>
>    A002072. The last pair of 89-smooth numbers is
>    9591468737351909375, 9591468737351909376.
>    3*89 can't occur after that.
>
>