[seqfan] Re: n = number of divisors of 2^n -1
Richard Mathar
mathar at strw.leidenuniv.nl
Wed Apr 21 19:34:54 CEST 2010
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
I downloaded b046801.txt and did a
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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