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 A051267 #11 Aug 17 2017 22:39:06
%S A051267 31,37,41,43,47,49,53,55,59,61,65,67,71,73,77,79,81,83,85,87,89,91,93,
%T A051267 95,97,99,101,103,106,107,109,111,113,115,116,117,118,119,121,122,123,
%U A051267 124,125,127,128,129,131,133,134,136,137,139,141,142,143,145,146,147
%N A051267 Numbers n such that maximal value of prime divisors of reduced residue system for n is 3.
%C A051267 Largest value of A001221(k) = 3 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 A051267 Michael De Vlieger, <a href="/A051267/b051267.txt">Table of n, a(n) for n = 1..2446</a>
%t A051267 Block[{n = 3, P}, P = Product[Prime@ i, {i, n}]; P + Position[#, n][[All, 1]] &@ Array[Max@ Map[PrimeNu, Cases[Range@ #, k_ /; CoprimeQ[#, k]]] &, 117, P + 1]] (* _Michael De Vlieger_, Aug 10 2017 *)
%Y A051267 Cf. A001221, A002110, A038566, A048597, A051250, A051265, A051266, A051268.
%K A051267 nonn
%O A051267 1,1
%A A051267 _Labos Elemer_