This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A216825 #11 Mar 14 2020 18:53:15
%S A216825 2,3,7,11,17,23,31,43,101,149,3109,47059,2217342227,1729101023519
%N A216825 Prime factors of the first 8 primary pseudoperfect numbers A054377.
%C A216825 See A054377 for comments, references, and links.
%e A216825 42 = 2*3*7 is the third primary pseudoperfect number, so 2, 3, 7 are members.
%e A216825 5 is not a factor of any of the first 8 primary pseudoperfect numbers, so 5 is not a member.
%t A216825 A054377 = Cases[Import["https://oeis.org/A054377/b054377.txt", "Table"], {_, _}][[All, 2]];
%t A216825 Union[First /@ Flatten[FactorInteger[A054377], 1]] (* _Robert Price_, Mar 14 2020 *)
%Y A216825 Cf. A054377, A216826, A236433.
%K A216825 nonn,fini,full
%O A216825 1,1
%A A216825 _Jonathan Sondow_, Sep 17 2012