A216825 Prime factors of the first 8 primary pseudoperfect numbers A054377.

2, 3, 7, 11, 17, 23, 31, 43, 101, 149, 3109, 47059, 2217342227, 1729101023519

Offset

1,1

Comments

See A054377 for comments, references, and links.

Links

Table of n, a(n) for n=1..14.

Example

42 = 2*3*7 is the third primary pseudoperfect number, so 2, 3, 7 are members.
5 is not a factor of any of the first 8 primary pseudoperfect numbers, so 5 is not a member.

Mathematica

A054377 = Cases[Import["https://oeis.org/A054377/b054377.txt", "Table"], {_, _}][[All, 2]];
Union[First /@ Flatten[FactorInteger[A054377], 1]] (* Robert Price, Mar 14 2020 *)

Crossrefs

Cf. A054377, A216826, A236433.

Sequence in context: A045324 A140460 A045325 * A094066 A330070 A350839

Adjacent sequences: A216822 A216823 A216824 * A216826 A216827 A216828

Keyword

nonn,fini,full

Author

Jonathan Sondow, Sep 17 2012

Status

approved