[seqfan] Re: Nice conjecture from Enrique Navarrete re divisors of triangular numbers A111273

[Fred Lunnon]

Oops! trying again ---

  By induction: if  q|(p-1)  then  q = a(q-1)  has appeared earlier; the only
divisor of  t_(p-1)  remaining is  p  itself, so  a(p-1) = p .    QED WFL



On 7/24/19, Fred Lunnon <fred.lunnon at gmail.com> wrote:
>   By induction: if  q|(p-1)  then  q = a(q-1)  has appeared earlier; the
> only
> divisor of  t_p  remaining is  p  itself, so  a(p-1) = p .    QED WFL
>
>
>
> On 7/24/19, Neil Sloane <njasloane at gmail.com> wrote:
>> E.N. noticed that in A111273 (definition: a(n) = smallest divisor of t_n
>> =
>> n(n+1)/2 that has not yet appeared in the sequence), it seems that
>> a(p-1)=p
>> for all odd primes p.
>> Surely this can't be a hard problem?
>>
>> It would follow if we knew that the smallest missing number (smn) in
>> A111273 (which is now A309195) is always >n/2.
>>
>> --
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>>
>