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 A330835 #23 Jan 24 2020 16:24:38 %S A330835 3,7,13,31,31,127,1093,307,8191,2801,1723,19531,3541,131071,5113, %T A330835 30941,8011,10303,524287,88741,17293,797161,28057,30103,292561,732541, %U A330835 86143,147073,12207031,5229043,3500201,459007,492103,552793,25646167,579883,598303,684757 %N A330835 Primes q appearing in A330832: that is, if A330832(n)=p*q, where p is prime and q=(p^k-1)/(p-1) is prime, then a(n)=q. %C A330835 The terms in the b-file are the same as those of A003424 with y=1, but with an ordering based on that of A330832. The ordering allows the inclusion of the only duplicate 2^5-1=31 and (5^3-1)/(5-1)=31. %H A330835 Walter Kehowski, <a href="/A330835/b330835.txt">Table of n, a(n) for n = 1..4731</a> %H A330835 G. Sobczyk, <a href="https://garretstar.com/secciones/publications/docs/monthly336-346.pdf">The Missing Spectral Basis in Algebra and Number Theory</a>, The American Mathematical Monthly 108(4), April 2001. %F A330835 a(n) = (A330833(n) ^ A330834(n) - 1) / (A330833(n) - 1). %e A330835 a(5)=31 since A330833(5)=5, A330834(5)=3, and (5^3-1)/(5-1) = 31 is prime. %Y A330835 Cf. A003424, A023194, A023195, A085104, A330832, A330833, A330834. %K A330835 nonn %O A330835 1,1 %A A330835 _Walter Kehowski_, Jan 08 2020