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 A330834 #15 Jan 23 2020 18:12:51 %S A330834 2,3,3,5,3,7,7,3,13,5,3,7,3,17,3,5,3,3,19,5,3,13,3,3,5,5,3,3,11,7,5,3, %T A330834 3,3,7,3,3,3,3,3,3,3,3,13,3,3,3,3,5,3,3,5,3,3,3,5,31,3,3,3,3,3,3,3,3, %U A330834 3,3,3,3,3,3,3,3,3,7,3,5,3,3,3,3,3,3,3,3 %N A330834 The exponents k of A330832, that is, if A330832(n)=p*q, where p is prime and q=(p^k-1)/(p-1) is prime, then a(n)=k. %H A330834 Walter Kehowski, <a href="/A330834/b330834.txt">Table of n, a(n) for n = 1..4731</a> %H A330834 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. %e A330834 a(5) = 3, and, since A330833(5)=5, then A330835(5)=(5^3-1)/(5-1) = 31 is prime. %Y A330834 Cf. A003424, A023194, A023195, A085104, A330832, A330833, A330835. %K A330834 nonn %O A330834 1,1 %A A330834 _Walter Kehowski_, Jan 08 2020