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 A051268 #15 Aug 17 2017 22:39:28
%S A051268 211,221,223,227,229,233,239,241,247,251,253,257,263,269,271,277,281,
%T A051268 283,289,293,299,307,311,313,317,319,323,331,337,341,343,347,349,353,
%U A051268 359,361,367,371,373,377,379,383,389,391,397,401,403,407,409,413
%N A051268 Numbers n such that maximal value of prime divisors of reduced residue system for n is 4.
%C A051268 Largest value of A001221(k) = 4 for 1 <= k <= n such that gcd(k, n) = 1, i.e., k in row n of A038566. - _Michael De Vlieger_, Aug 10 2017
%H A051268 Michael De Vlieger, <a href="/A051268/b051268.txt">Table of n, a(n) for n = 1..10000</a>
%t A051268 Block[{n = 4, P}, P = Product[Prime@ i, {i, n}]; P + Position[#, n][[All, 1]] &@ Array[Max@ Map[PrimeNu, Cases[Range@ #, k_ /; CoprimeQ[#, k]]] &, 175, P + 1]] (* _Michael De Vlieger_, Aug 10 2017 *)
%Y A051268 Cf. A001221, A002110, A006862, A038566, A048597, A051250, A051265, A051266, A051267.
%K A051268 nonn
%O A051268 1,1
%A A051268 _Labos Elemer_
%E A051268 More terms from _Michael De Vlieger_, Aug 10 2017