A241268 - OEIS

%I #10 Sep 08 2022 08:46:07

%S 2,4,5,10,12,13,14,15,17,18,19,20,21,22,23,24,26,27,28,29,30,31,33,34,

%T 36,37,39,41,42,43,44,45,46,47,49,51,52,53,55,56,57,59,60,61,62,63,64,

%U 66,67,68,69,70,71,72,73,74,75,76,80,81,82,83,84,85,86,88

%N Numbers n such that (n+1)^7-n^7 is not prime.

%H Vincenzo Librandi, <a href="/A241268/b241268.txt">Table of n, a(n) for n = 1..10000</a>

%e 4 is in this sequence because 5^7 - 4^7 = 61741 = 29*2129.

%t Select[Range[100], ! PrimeQ[(# + 1)^7 - #^7] &]

%o (Magma) [n: n in [0..350] | not IsPrime((n+1)^7-n^7)];

%Y Complement of A113826.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Apr 20 2014