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

Author

Jonathan Sondow, Sep 17 2012

Keywords

• nonn
• fini
• full

Comments

See A054377 for comments, references, and links.

Examples

			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.
		

Crossrefs

Cf. A054377, A216826, A236433.

Programs

Mathematica

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