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 A197309 #15 Jun 21 2017 23:16:29 %S A197309 1,3,9,37,111,333,333667,1001001,3003003,12345679,37037037,111111111 %N A197309 Divisors of the 9th repunit 111111111. %C A197309 The prime factorization of (10^9 - 1)/9 is 3^2 * 37 * 333667. - _Alonso del Arte_, Apr 27 2014 %H A197309 <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a>. %t A197309 Divisors[(10^9 - 1)/9] (* _Alonso del Arte_, Apr 27 2014 *) %o A197309 (PARI) divisors(10^9\9) \\ _Charles R Greathouse IV_, Jun 21 2017 %Y A197309 Cf. A109492, A197308, A070529, A018282, A018766, A027894, A027893, A027892, A027891, A027890, A027889, A027895. %K A197309 nonn,fini,full,easy %O A197309 1,2 %A A197309 _M. F. Hasler_, Oct 13 2011