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 A023517 #14 Oct 09 2022 05:21:19
%S A023517 5,7,17,19,71,11,23,109,37,449,191,379,881,101,83,521,257,227,41,2591,
%T A023517 31,149,1231,83,79,743,29,17,3079,41,4159,997,9521,109,1607,439,853,
%U A023517 1361,107,397,167,3457,2633,1901,1153,3499,1307,2531,79,13339,9281,929
%N A023517 Greatest prime divisor of prime(n)*prime(n-1) - 1.
%H A023517 Hugo Pfoertner, <a href="/A023517/b023517.txt">Table of n, a(n) for n = 2..10000</a>
%o A023517 (PARI) gpf(x) = {my (f=factor(x)); f[#f[,2],1]};
%o A023517 a023517(pmax) = {my(pp=2); forprime (p=3, pmax, print1(gpf(pp*p-1),", "); pp=p)};
%o A023517 a023517(300) \\ _Hugo Pfoertner_, Oct 09 2022
%Y A023517 Cf. A006530, A023515, A023525.
%K A023517 nonn
%O A023517 2,1
%A A023517 _Clark Kimberling_
%E A023517 a(1)=2 removed by _Sean A. Irvine_, Jun 05 2019