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 A023569 #17 Dec 29 2015 03:03:43
%S A023569 2,2,2,5,7,2,5,13,7,17,19,5,11,5,7,29,2,17,7,19,5,43,47,7,5,13,53,11,
%T A023569 31,2,67,17,73,37,11,5,41,17,11,89,47,19,97,7,13,11,7,113,23,59,17,31,
%U A023569 127,13,19,67,137,139,7,29,19,11,31,157,41,167,43,173,7,89
%N A023569 Greatest prime divisor of prime(n) - 3.
%C A023569 a(n) = 2 if prime(n) is in A057733. - _Robert Israel_, Dec 28 2015
%H A023569 Robert Israel, <a href="/A023569/b023569.txt">Table of n, a(n) for n = 3..10000</a>
%p A023569 seq(max(numtheory:-factorset(ithprime(i)-3)), i=3..100); # _Robert Israel_, Dec 28 2015
%t A023569 Table[FactorInteger[Prime[n] - 3] [[-1, 1]], {n, 3, 100}] (* _Vincenzo Librandi_, Dec 29 2015 *)
%o A023569 (PARI) a(n) = vecmax(factor(prime(n)-3)[,1]); \\ _Michel Marcus_, Dec 29 2015
%Y A023569 Cf. A023568, A057733.
%K A023569 nonn
%O A023569 3,1
%A A023569 _Clark Kimberling_
%E A023569 Corrected by _Robert Israel_, Dec 29 2015