OFFSET
1,2
COMMENTS
EXAMPLE
1^1 + 2^1 = 3 is prime (k = 2).
1^2 + 2^2 = 5 is prime (k = 2).
1^4 + 2^4 = 17 is prime (k = 2).
1^8 + 2^8 = 257 is prime (k = 2).
1^16 + 2^16 = 65537 is prime (k = 2).
1^1440 + 2^1440 + 3^1440 + 4^1440 + 5^1440 = 3.287049497374559048967261852*10^1006 = 3287049497374559048967261852 ... 458593539025033893379 is prime (k = 5).
MATHEMATICA
lst={}; Do[s=0; Do[If[PrimeQ[s+=n^x], AppendTo[lst, x]; Print[Date[], x]], {n, 4!}], {x, 7!}]; lst
PROG
(PARI) a(n)=for(k=1, 10^3, if(ispseudoprime(sum(i=1, k, i^n)), return(k)))
n=1; while(n<5000, if(a(n), print1(n, ", ")); n++) \\ Derek Orr, Jun 06 2014
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Vladimir Joseph Stephan Orlovsky, Aug 12 2009
EXTENSIONS
Definition improved by Derek Orr, Jun 06 2014
STATUS
approved