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

2, 85, 4, 33, 6, 7, 8, 13, 22, 13, 16, 41, 28, 15, 22, 19, 24, 23, 54, 31, 22, 27, 56, 61, 38, 29, 40, 37, 34, 61, 32, 35, 82, 35, 46, 43, 40, 49, 58, 67, 42, 55, 58, 49, 46, 61, 58, 61, 68, 73, 92, 63, 94, 77, 166, 57, 82, 63, 72, 109, 76, 121, 82, 79, 86, 67, 72, 77, 82, 71, 98

Offset

1,1

Comments

a(n) = n+1 iff n is in A154535.

Links

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

Example

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.

Prog

(Python)
import sympy
from sympy import isprime
def a(n):
..for k in range(n+1, 10**4):
....if isprime(k**16+n**16):
......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^16+n^16), return(k)))
n=1; while(n<100, print1(a(n), ", "); n++)

Crossrefs

Cf. A158979, A089489, A242554.

Sequence in context: A181119 A293707 A157315 * A078166 A101578 A041881

Adjacent sequences: A244944 A244945 A244946 * A244948 A244949 A244950

Keyword

nonn

Author

Derek Orr, Jul 08 2014

Status

approved