[seqfan] Re: A269254 and A034807

Don Reble djr at nk.ca
Sat Oct 28 00:59:29 CEST 2017

> the sequence to a(10000) showing (currently) 300 unknowns.
> ... I'll be actively working on reducing that number in
> the coming weeks/months:

    In case some people don't know.
    For those s() sequences with s(0)=1, s(1)=n+1:
    if 2k+1 is composite, then s(k) is composite.
    On average, it's faster to test 2k+1 and maybe s(k),
    than to test s(k).

Don Reble  djr at nk.ca

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