A162294 - OEIS

%I #15 Aug 25 2016 03:10:42

%S 4,6,8,12,16,22,28,34,44,50,54,56,58,76,78,88,110,112,118,134,138,156,

%T 162,166,168,170,188,190,200,204,208,210,226,230,236,244,250,268,274,

%U 302,310,314,322,324,340,344,356,364,368,378,382,390,398,400,420,424

%N Numbers k such that k^3-k^2-k-1 is prime.

%H Ivan Neretin, <a href="/A162294/b162294.txt">Table of n, a(n) for n = 1..10000</a>

%F k^3-k^2-k-1 = A162295(n), where k=a(n).

%F Sum_{i=1..n} a(i) = Sum_{i=1..n} i * ( pi(i^3 - i^2 - i - 1) - pi(i^3 - i^2 - i - 2) ). - _Wesley Ivan Hurt_, May 24 2013

%e k=4 is in the sequence because 4^3-4^2-4-1=43 is prime.

%e k=6 is in the sequence because 6^3-6^2-6-1=173 is prime.

%t lst={};Do[p=n^3-n^2-n-1;If[PrimeQ[p],AppendTo[lst,n]],{n,2,6!}];lst

%Y Cf. A087908, A111501, A162291, A162293, A162295 (corresponding primes).

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jun 30 2009

%E Edited by _R. J. Mathar_, Jul 02 2009