A246666 - OEIS

%I #28 Sep 11 2014 12:51:56

%S 1,3,5,9,31,43,45,51,71,89,135,141,145,149,159,163,169,183,185,225,

%T 233,241,255,261,271,281,283,285,299,309,311,313,355,395,401,411,415,

%U 423,429,435,449,453,485,491,541,551,561,579,583,589,603,621,625,635,681

%N Numbers n such that n^3 + (n+1)^3 + (n+3)^3 is prime.

%C All terms are odd. - _Jon Perry_, Sep 11 2014

%H Nathaniel Johnston, <a href="/A246666/b246666.txt">Table of n, a(n) for n = 1..10000</a>

%e a(5)=31 since 31^3+(31+1)^3+(31+3)^3=101863 is prime.

%p isA246666 := proc (n) return isprime(n^3+(n+1)^3+(n+3)^3) end proc; seq(`if`(isA246666(2*n-1), 2*n-1, NULL), n = 1 .. 400); # _Nathaniel Johnston_, Sep 09 2014

%o (PARI) for(n=0,10^3,if(isprime(n^3+(n+1)^3+(n+3)^3),print1(n,", "))); \\ _Joerg Arndt_, Sep 09 2014

%o (Python)

%o from sympy import isprime

%o A246666_list = [n for n in range(1,10**5) if isprime(3*n*(n*(n+4)+10)+28)]

%o # _Chai Wah Wu_, Sep 09 2014

%K nonn

%O 1,2

%A _Carmine Suriano_, Sep 01 2014