Not yet in OEIS: Product of odd divisors of n?

Richard Mathar mathar at
Thu Jun 26 22:25:18 CEST 2008

On Wed, Jun 25, 2008 at 8:12 AM, Jonathan Post <jvospost3 at> wrote:
> Primes with Lucas number digital root.
> This is to A000032 as A003147 is to A000045.

DIGITAL root would be utterly boring.

PRIMITIVE root is pretty uninteresting too; lots of numbers are
primitive roots for prime mods, right?  I suppose phi(p-1), which I
guess could be small for those special primes where p-1 has a lot of
different prime factors.  Still.  At least this is actually a property
of the numbers.

But wait, you're talking about ?  It already covers
Lucas, since the only "Fibonacci" thing about it is that the numbers
satisfy the Fibonacci-type equation g^2 = g+1, not that they are
actually 1,1,2,3,5,8,...

So the correct analogy is A003147 is to A000032 as A003147 is to A000045.

--Joshua Zucker

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