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 A242871 #15 Dec 17 2014 10:54:08
%S A242871 1,2,4,5,6,7,9,11,12,15,19,21,23,27,30,35,39,42,43,45,51,57,63,67,75,
%T A242871 81,83,87,99,103,111,120,123,129,131,147,159,163,171,183,195,203,219,
%U A242871 223,237,243,255,259,275,291,297,303,315,323,331,339,345,354,363,381,387
%N A242871 Numbers n such that (n^n-3^3)/(n-3) is an integer.
%C A242871 These are also numbers n such that (n^3-3^n)/(n-3) is an integer.
%H A242871 Robert Israel, <a href="/A242871/b242871.txt">Table of n, a(n) for n = 1..1149</a>
%e A242871 (5^5-3^3)/(5-3) = 3098/2 = 1549 is an integer. Thus 5 is a member of this sequence.
%p A242871 filter:= proc(n) (n^n - 27) mod (n-3) = 0 end proc:
%p A242871 select(filter, [1,2,$4..1000]); # _Robert Israel_, May 25 2014
%t A242871 Join[{1,2},Select[Range[4,400],IntegerQ[(#^#-27)/(#-3)]&]] (* _Harvey P. Dale_, Dec 17 2014 *)
%o A242871 (PARI) for(n=1,1000,if(n!=3,s=(n^n-3^3)/(n-3);if(floor(s)==s,print(n))))
%Y A242871 Cf. A242870.
%K A242871 nonn
%O A242871 1,2
%A A242871 _Derek Orr_, May 24 2014