[seqfan] Re: Nomination for 250000.

Neil Sloane njasloane at gmail.com
Sat Nov 15 12:51:03 CET 2014


Dear Juri,
Please submit these two sequences to the OEIS,
and tell me the A-numbers:

"Numbers n such that n, 2^n - 1 and binomial coefficient(2^n - 1, n) are
all squarefree: 1, 2, 3, 11, 29, 31, 51, 55, 57, ... (finite)

Primes p such that 2^p - 1 is not squarefree: 359, 397, 419, ...
(infinite). "

By the way, the second one should have a cross-reference
saying "These are the primes in A049094."

Thank you


Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com


On Fri, Nov 14, 2014 at 5:51 PM, юрий герасимов <2stepan at rambler.ru> wrote:

>
> Numbers n such that n, 2^n - 1 and binomial coefficient(2^n - 1, n) are
> all squarefree: 1, 2, 3, 11, 29, 31, 51, 55, 57, ... (finite)
> or Primes p such that 2^p - 1 is not squarefree: 359, 397, 419, ...
> (infinite). JSG.


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