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 A023509 #18 May 07 2025 01:02:37
%S A023509 3,2,3,2,3,7,3,5,3,5,2,19,7,11,3,3,5,31,17,3,37,5,7,5,7,17,13,3,11,19,
%T A023509 2,11,23,7,5,19,79,41,7,29,5,13,3,97,11,5,53,7,19,23,13,5,11,7,43,11,
%U A023509 5,17,139,47,71,7,11,13,157,53,83,13,29,7,59,5,23,17,19,3,13
%N A023509 Greatest prime divisor of prime(n) + 1.
%C A023509 A005382 is the records subsequence of this sequence. - _David James Sycamore_, May 05 2025
%H A023509 T. D. Noe, <a href="/A023509/b023509.txt">Table of n, a(n) for n = 1..10000</a>
%F A023509 a(n) = A006530(A008864(n)). - _R. J. Mathar_, Feb 06 2019
%t A023509 Table[FactorInteger[Prime[n] + 1][[-1, 1]], {n, 100}]
%o A023509 (PARI) A023509(n) = {local(f);f=factor(prime(n)+1);f[matsize(f)[1],1]} \\ _Michael B. Porter_, Feb 02 2010
%Y A023509 Cf. A006530, A008864, A005382.
%K A023509 nonn
%O A023509 1,1
%A A023509 _Clark Kimberling_