[seqfan] Re: nonpowers in A001481

[Charles Greathouse]

But for 9,  gcd{i, 2j's, k's} = gcd {2} = 2 ≠ 1, so it shouldn't be a
member.  For 18, gcd{i, 2j's, k's} = gcd {1, 2} = 1 so it should be a
member.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Sun, Jan 16, 2011 at 7:48 AM, Joerg Arndt <arndt at jjj.de> wrote:
> * N. J. A. Sloane <njas at research.att.com> [Jan 15. 2011 19:41]:
>> [...]
>
>> Me: Yes! You might mention that these are the set-difference Athis \ Athat.
>>
>  http://oeis.org/draft/A180161
>
>> Also that these are the numbers n = 2^i Product_{p == 3 mod 4} p^2j
>> Product_{p == 1 mod 4 } p^k where gcd{i, 2j's, k's} = 1
>
> Not so sure about this one: 9 is not a term, 18 is a term.
>
>>
>> Neil
>>
>
> Ready for merciless editing.
>
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