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A244947 Least number k > n such that k^16 + n^16 is prime.

%I A244947 #11 May 22 2025 10:21:38
%S A244947 2,85,4,33,6,7,8,13,22,13,16,41,28,15,22,19,24,23,54,31,22,27,56,61,
%T A244947 38,29,40,37,34,61,32,35,82,35,46,43,40,49,58,67,42,55,58,49,46,61,58,
%U A244947 61,68,73,92,63,94,77,166,57,82,63,72,109,76,121,82,79,86,67,72,77,82,71,98
%N A244947 Least number k > n such that k^16 + n^16 is prime.
%C A244947 a(n) = n+1 iff n is in A154535.
%H A244947 Jens Kruse Andersen, <a href="/A244947/b244947.txt">Table of n, a(n) for n = 1..10000</a>
%e A244947 10^16 + 11^16 = 55949729863572161 is not prime. 10^16 + 12^16 = 2^16*(5^16+6^16) is not prime. 10^16 + 13^16 = 675416609183179841 is prime. Thus a(10) = 13.
%o A244947 (Python)
%o A244947 import sympy
%o A244947 from sympy import isprime
%o A244947 def a(n):
%o A244947   for k in range(n+1,10**4):
%o A244947     if isprime(k**16+n**16):
%o A244947       return k
%o A244947 n = 1
%o A244947 while n < 100:
%o A244947   print(a(n),end=', ')
%o A244947   n += 1
%o A244947 (PARI) a(n)=for(k=n+1,10^4,if(isprime(k^16+n^16),return(k)))
%o A244947 n=1;while(n<100,print1(a(n),", ");n++)
%Y A244947 Cf. A158979, A089489, A242554.
%K A244947 nonn
%O A244947 1,1
%A A244947 _Derek Orr_, Jul 08 2014