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 A117366 #18 Jun 07 2025 05:21:47
%S A117366 2,3,5,3,7,5,11,3,5,7,13,5,17,11,7,3,19,5,23,7,11,13,29,5,7,17,5,11,
%T A117366 31,7,37,3,13,19,11,5,41,23,17,7,43,11,47,13,7,29,53,5,11,7,19,17,59,
%U A117366 5,13,11,23,31,61,7,67,37,11,3,17,13,71,19,29,11,73,5,79,41,7,23,13,17,83,7
%N A117366 a(n) = smallest prime greater than the largest prime dividing n.
%H A117366 Reinhard Zumkeller, <a href="/A117366/b117366.txt">Table of n, a(n) for n = 1..10000</a>
%F A117366 a(n) = A151800(A006530(n)). - _Reinhard Zumkeller_, Apr 06 2015
%F A117366 a(n) = A000040(A159081(n)). - _Antti Karttunen_, Jan 15 2020
%e A117366 5 is the largest prime dividing 10. So a(10) is the smallest prime > 5, which is 7.
%t A117366 Table[Prime[PrimePi[FactorInteger[n][[Length[FactorInteger[n]]]][[1]]]+1], {n, 80}] (* _Stefan Steinerberger_, Apr 09 2006 *)
%o A117366 (Haskell)
%o A117366 a117366 = a151800 . a006530 -- _Reinhard Zumkeller_, Apr 06 2015
%o A117366 (PARI) A117366(n) = if(1==n, 2, nextprime(1+vecmax(factor(n)[, 1]))); \\ _Antti Karttunen_, Jan 15 2020
%Y A117366 Cf. A117364, A117365, A117367.
%Y A117366 Cf. A000040, A006530, A151800, A159081.
%K A117366 nonn
%O A117366 1,1
%A A117366 _Leroy Quet_, Mar 10 2006
%E A117366 More terms from _Stefan Steinerberger_, Apr 09 2006