A307843 Divisors of Fermat numbers.

1, 3, 5, 17, 257, 641, 65537, 114689, 274177, 319489, 974849, 2424833, 6700417, 13631489, 26017793, 45592577, 63766529, 167772161, 825753601, 1214251009, 4294967297, 6487031809, 70525124609, 190274191361, 311453532161, 646730219521, 2710954639361

Offset

1,2

Comments

Has both A000215 and A023394 as subsequences. Outside these are 1 and the composite proper divisors of Fermat numbers, namely 311453532161, 2983954661377, 7313319444481, ...

Links

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..58

Example

311453532161 is included because it divides 2^(2^11) + 1. It is not included in A023394 because it is composite.

Crossrefs

Cf. A000215, A023394, A050922, A094358.

Sequence in context: A272060 A333873 A058910 * A023394 A176689 A256510

Adjacent sequences: A307840 A307841 A307842 * A307844 A307845 A307846

Keyword

nonn

Author

Jeppe Stig Nielsen, Jul 24 2019

Status

approved