[seqfan] A076978

[Don Reble]

Seqfans:

> %S A076978 1,2,6,30,6,210,6,2310,2730,30,39270,7410,42,7590,46410,1272810...
> %C A076978 Apparently a duplicate of A074168.
>            - _R. J. Mathar_, Sep 20 2008

    Yeah, it's a duplicate. I propose a replacement.

    A074168 has "1,2" and then squarefree multiples of 6.
    Which squarefree multiples are in the sequence? Perhaps all of
    them: but that would imply that the Twin Prime Conjecture is true.

    The replacement: a(n) is the least positive integer x such that
    - the squarefree part of 6x is 6*b(n), and
    - 6x-1 and 6x+1 are prime.
    Or else "0" if there's no such x.
    B(n) is the n'th number that is both squarefree and coprime to 6.

    (BTW, that b(n) isn't in the OEIS.)

-- 
Don Reble  djr at nk.ca