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A244950 Least number k > n such that k^128 + n^128 is prime.

%I A244950 #14 Jun 19 2020 16:28:05
%S A244950 120,113,106,259,304,85,212,135,158,47,62,985,84,47,518,485,178,169,
%T A244950 106,27,88,139,632,47,44,643,194,209,606,1529,32,113,1094,139,754,647,
%U A244950 38,45,262,69,94,631,90,527,326,195,54,277,232,187,554,189,78,799,216,131,1132,173
%N A244950 Least number k > n such that k^128 + n^128 is prime.
%C A244950 a(n) = n+1 iff n is in A215431.
%H A244950 Jens Kruse Andersen, <a href="/A244950/b244950.txt">Table of n, a(n) for n = 1..1000</a>
%e A244950 The n-value for which n^128 + 1 is prime (sequence A056994) is n = 120 (where n > 1 by definition). Thus a(1) = 120.
%t A244950 lnk[n_]:=Module[{k=n+1,n128=n^128},While[!PrimeQ[n128+k^128],k++];k]; Array[lnk,60] (* _Harvey P. Dale_, Apr 22 2018 *)
%o A244950 (Python)
%o A244950 import sympy
%o A244950 from sympy import isprime
%o A244950 def a(n):
%o A244950     for k in range(n+1,10**4):
%o A244950         if isprime(k**128+n**128):
%o A244950             return k
%o A244950 for n in range(1, 100):
%o A244950     print(a(n), end=', ')
%o A244950 (PARI) a(n)=for(k=n+1,10^4,if(isprime(k^128+n^128),return(k)))
%o A244950 n=1;while(n<100,print1(a(n),", ");n++)
%Y A244950 Cf. A158979, A089489, A242557.
%K A244950 nonn
%O A244950 1,1
%A A244950 _Derek Orr_, Jul 08 2014