# [seqfan] Re: n = number of divisors of 2^n -1

Leroy Quet q1qq2qqq3qqqq at yahoo.com
Wed Apr 21 19:51:09 CEST 2010

```I'm sorry. I don't know what you just did.

The number of divisors of 2^12 -1 is 24, not 12. So, 12 is not in the list.

Thanks,
Leroy Quet

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--- On Wed, 4/21/10, Richard Mathar <mathar at strw.leidenuniv.nl> wrote:

> From: Richard Mathar <mathar at strw.leidenuniv.nl>
> Subject: [seqfan] Re: n = number of divisors of 2^n -1
> To: seqfan at seqfan.eu
> Date: Wednesday, April 21, 2010, 5:34 PM
>
> lq> From: Leroy Quet <q1qq2qqq3qqqq at yahoo.com>
> lq> To: seqfan at seqfan.eu
> lq> Subject: [seqfan]  n = number of divisors of
> 2^n -1
> lq>
> lq> I get the sequence where a positive integer n is
> included if
> lq> n = the number of divisors of 2^n - 1,
> lq> begins:
> lq> 1,2,4,6,8,16
>
>   sort -n -k 2 b046801.txt
> which says that 12 is also in the list at n=21. Other
> members in the list are
>
> 0 1 2 4 6 8 12 16 24 32 48 64 96 128 144 160 192 256 384
> 512 768
> 1024 1536 2048 3072 4096 4608 6144 8192 9216 10240 12288
> 16384 24576
> 32768 49152 65536 73728 98304 131072 147456 196608 262144
> 294912
> 393216 524288 655360 786432 etc
>
> but this is not necessarily a complete set, because the
> bfile
> is finite.
>
>
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>

```