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Prime factors of the first 8 primary pseudoperfect numbers A054377.
3

%I #11 Mar 14 2020 18:53:15

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

%N Prime factors of the first 8 primary pseudoperfect numbers A054377.

%C See A054377 for comments, references, and links.

%e 42 = 2*3*7 is the third primary pseudoperfect number, so 2, 3, 7 are members.

%e 5 is not a factor of any of the first 8 primary pseudoperfect numbers, so 5 is not a member.

%t A054377 = Cases[Import["https://oeis.org/A054377/b054377.txt", "Table"], {_, _}][[All, 2]];

%t Union[First /@ Flatten[FactorInteger[A054377], 1]] (* _Robert Price_, Mar 14 2020 *)

%Y Cf. A054377, A216826, A236433.

%K nonn,fini,full

%O 1,1

%A _Jonathan Sondow_, Sep 17 2012