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 A003530 #23 Jul 02 2024 05:02:06 %S A003530 1,7,49,127,337,889,2359,6223,16513,42799,299593,2097151 %N A003530 Divisors of 2^21 - 1. %H A003530 <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a> %t A003530 Divisors[2^21 - 1] (* _Paolo Xausa_, Jul 02 2024 *) %o A003530 (PARI) divisors(2^21-1) \\ _Charles R Greathouse IV_, Jun 21 2017 %Y A003530 Row n = 21 of A361438. %K A003530 nonn,fini,full,easy %O A003530 1,2 %A A003530 _N. J. A. Sloane_