A244932 - OEIS

%I #9 Jul 12 2014 22:43:37

%S 2,13,10,17,6,37,12,13,16,27,24,71,16,31,64,43,18,43,26,23,32,29,24,

%T 79,32,53,34,61,92,47,40,33,34,57,36,47,40,53,40,79,44,43,68,91,68,57,

%U 66,61,60,53,58,83,60,91,94,61,82,61,70,101,82,71,68,145,82,67,76,69,100

%N Least number k > n such that k^8 + n^8 is prime.

%C a(n) = n+1 iff n is in A153504.

%H Jens Kruse Andersen, <a href="/A244932/b244932.txt">Table of n, a(n) for n = 1..10000</a>

%e 13^8 + 14^8 = 2291519777 is not prime, 13^8 + 15^8 = 3378621346 is not prime. 13^8 + 16^8 = 5110698017 is prime. Thus a(13) = 16.

%o (Python)

%o import sympy

%o from sympy import isprime

%o def a(n):

%o ..for k in range(n+1,10**4):

%o ....if isprime(k**8+n**8):

%o ......return k

%o n = 1

%o while n < 100:

%o ..print(a(n),end=', ')

%o ..n += 1

%o (PARI) a(n)=for(k=n+1,10^4,if(isprime(k^8+n^8),return(k)))

%o n=1;while(n<100,print1(a(n),", ");n++)

%Y Cf. A158979, A089489, A242553.

%K nonn

%O 1,1

%A _Derek Orr_, Jul 08 2014