A244932 Least number k > n such that k^8 + n^8 is prime.

2, 13, 10, 17, 6, 37, 12, 13, 16, 27, 24, 71, 16, 31, 64, 43, 18, 43, 26, 23, 32, 29, 24, 79, 32, 53, 34, 61, 92, 47, 40, 33, 34, 57, 36, 47, 40, 53, 40, 79, 44, 43, 68, 91, 68, 57, 66, 61, 60, 53, 58, 83, 60, 91, 94, 61, 82, 61, 70, 101, 82, 71, 68, 145, 82, 67, 76, 69, 100

Offset: 1

Author

Derek Orr, Jul 08 2014

Keywords

• nonn

Comments

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

Examples

			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.
		

Links

• Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A158979, A089489, A242553.

Programs

PARI

a(n)=for(k=n+1,10^4,if(isprime(k^8+n^8),return(k)))
n=1;while(n<100,print1(a(n),", ");n++)

Python

import sympy
from sympy import isprime
def a(n):
  for k in range(n+1,10**4):
    if isprime(k**8+n**8):
      return k
n = 1
while n < 100:
  print(a(n),end=', ')
  n += 1