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 A242788 #11 Jan 29 2015 10:33:05 %S A242788 1,2,4,5,6,7,9,11,13,15,16,27,31,33,36,55,73,91,133,241,249,366,367, %T A242788 491,513,577,733,757,871,913,971,991,1233,1333,1576,1711,1927,2071, %U A242788 2346,2593,2731,3307,3391,3529,4005,4591,5113,5371,5409,5671,5793,6567,6801,7465,7591 %N A242788 Numbers n such that (n^n-3)/(n-3) is an integer. %C A242788 For n > 6, equivalent to n such that n^n = 3 mod n-3. - _Chai Wah Wu_, Jan 19 2015 %H A242788 Chai Wah Wu, <a href="/A242788/b242788.txt">Table of n, a(n) for n = 1..4388</a> %e A242788 (6^6-3)/(6-3) = 46653/3 = 15551 is an integer. Thus 6 is a member of this sequence. %t A242788 Select[ Range@ 7600, Mod[ PowerMod[#, #, # - 3] - 3, # - 3] == 0 &] (* _Robert G. Wilson v_, Jan 21 2015 *) %o A242788 (PARI) for(n=1,10^4,if(n!=3,s=(n^n-3)/(n-3);if(floor(s)==s,print(n)))) %o A242788 (Python) %o A242788 A242788_list = [1,2,4,5,6] + [n for n in range(7,10**6) if pow(n, n, n-3) == 3] %o A242788 # _Chai Wah Wu_, Jan 19 2015 %Y A242788 Cf. A242787. %K A242788 nonn %O A242788 1,2 %A A242788 _Derek Orr_, May 22 2014