[seqfan] Re: A026480

[Charles Greathouse]

It appears to be A026478, but defined to start with 1, 2, 4. I'll edit the
sequence accordingly.

Charles Greathouse
Case Western Reserve University

On Thu, Sep 22, 2016 at 2:03 AM, <israel at math.ubc.ca> wrote:

> A026480: "a(n) = least positive integer > a(n-1) and not a(i)*a(j)*a(k)
> for 1<=i<=j<=k<=n." has Data 1, 2, 4, 5, 6, 7, 9, 11, 13, 15, 17, 19, 21,
> 23, 27, 29, 31, 33, 37, 39, 41, 43, 47, 51, 53, 57, 59, 61, 67, 69.
>
> This doesn't make any sense to me. Since a(1) = 1, any a(n) =
> a(i)*a(j)*a(k) for the case i=j=1, k=n. Or if you don't allow this, the
> sequence would be the same as A026478: "a(n) = least positive integer >
> a(n-1) and not of form a(i)*a(j)*a(k) for 1<=i<=j<=k<n."
>
> What is this sequence supposed to be?
>
> Cheers,
> Robert
>
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