OFFSET
1,1
COMMENTS
a(n) = n+1 iff n is in A153504.
LINKS
Jens Kruse Andersen, Table of n, a(n) for n = 1..10000
EXAMPLE
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.
PROG
(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
(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++)
CROSSREFS
KEYWORD
nonn
AUTHOR
Derek Orr, Jul 08 2014
STATUS
approved