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Numbers n such that 1 + n + n^3 + n^5 is prime.
5

%I #11 Sep 08 2022 08:45:28

%S 2,4,8,20,22,32,36,50,54,62,64,72,78,84,86,90,92,94,96,98,112,124,134,

%T 144,146,216,224,238,240,246,250,256,262,276,294,296,298,300,314,334,

%U 370,378,382,392,400,402,406,420,430,450,472,480,482,494,510,512,526

%N Numbers n such that 1 + n + n^3 + n^5 is prime.

%C All numbers n have to be even, because sum of 3 odd + 1 is even and can't be prime >3.

%H Vincenzo Librandi, <a href="/A124154/b124154.txt">Table of n, a(n) for n = 1..1000</a>

%t Do[If[PrimeQ[1 + n + n^3 + n^5], Print[n]], {n, 1, 300}]

%t Select[Range[1000], PrimeQ[Total[#^Range[1, 5, 2]] + 1] &] (* _Vincenzo Librandi_, Jun 27 2014 *)

%o (PARI) forstep(n=2,1000,2,if(isprime(1 + n + n^3 + n^5), print1(n","))) \\ _Franklin T. Adams-Watters_, Apr 09 2009

%o (Magma) [n: n in [0..600] | IsPrime(s) where s is 1+&+[n^i: i in [1..5 by 2]]]; // _Vincenzo Librandi_, Jun 27 2014

%Y Cf. A049407, similar sequences listed in A244376.

%K nonn,easy

%O 1,1

%A _Artur Jasinski_, Dec 13 2006

%E More terms from _Franklin T. Adams-Watters_, Apr 09 2009