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 A133024 #14 Jul 30 2023 14:11:18 %S A133024 1,2,4,8,16,32,64,127,254,508,1016,2032,4064,8128 %N A133024 Divisors of 8128, the 4th perfect number. %C A133024 127 is the 4th Mersenne prime: A000668. %C A133024 The number of divisors of the 4th perfect number is 2*A000043(4)=A061645(4)=14. %C A133024 For the structure of this sequence and its binary expansion, see A135654. %H A133024 <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a> %H A133024 Omar E. Pol, <a href="http://www.polrpimos.com">Determinacion geometrica de los numeros primos y perfectos</a>. %F A133024 For n=1..7 : a(n) = 2^(n-1). For n=8..14: a(n) = 2^(n-1) - 2^(n-8) = A000668(4)*2^(n-8). %t A133024 Divisors[8128] (* _Harvey P. Dale_, Jul 30 2023 *) %o A133024 (PARI) divisors(8128) \\ _Charles R Greathouse IV_, Jun 21 2017 %Y A133024 Cf. A018254, A018487. Perfect numbers: A000396. %Y A133024 Cf. A000079, A000668, A061645, A133033, A135654. %K A133024 fini,full,nonn,easy %O A133024 1,2 %A A133024 _Omar E. Pol_, Oct 26 2007, Mar 03 2008, Dec 27 2008