Which Positive Integers Can Be Written as x4 + 4y4 to Form Prime Numbers?

In summary, the conversation discusses finding prime numbers that can be written in the form p = x4 + 4y4, where x and y are positive integers. It is mentioned that any such prime numbers must be congruent to 1 mod 4 and that one of the terms in the sum must be divisible by 5 for it to be prime. The conversation also mentions factoring x4 + 4y4 over the Gaussian integers and the importance of showing that the smaller factor is greater than 1. Finally, it is noted that the conversation is only providing hints and additional details can be found through private messaging.
  • #1
sachinism
66
0
Find all prime numbers p that can be written p = x4 + 4y4 , where x, y are positive
integers.
 
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  • #2
Do you know that any such prime numbers exist?
 
  • #3
Factor x4 + 4y4.
 
  • #4
CRGreathouse said:
Factor x4 + 4y4.

Factor, what, over the gaussian integers? In that case we know that a prime must be congruent to 1 mod 4. Also, other than 5, which is a solution, exactly one of the terms is divisible by 5, for the sum to be prime.
 
  • #5
robert Ihnot said:
Factor, what, over the gaussian integers? In that case we know that a prime must be congruent to 1 mod 4. Also, other than 5, which is a solution, exactly one of the terms is divisible by 5, for the sum to be prime.

x4 + 4y4 factors over Z.
 
  • #6
Petek said:
x4 + 4y4 factors over Z.

Shiver me timbers, I do see that is correct! So all we'd have to show is that the smaller factor exceeds 1.
 
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  • #7
Petek said:
x4 + 4y4 factors over Z.

Would anyone care to explain this in overly simplistic terms for a mathematically oriented, but untrained, layman such as myself? I mean, I know what "Z" is and I know what "factors" and "factorizations" are (at least simplistically speaking...), and I even am familiar with Gaussian versus, say, Eisenstein integers (again, simplistically speaking...), but the rest rather escapes me. In other words I am not following the logical train of thought that is obvious to other posters upon this thread...Raphie
 
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  • #8
We're just giving hints because the original question probably is homework. I'll send you a PM with more details.
 

1. What are prime numbers of given form?

Prime numbers of given form are numbers that are only divisible by 1 and themselves. They are often expressed in the form of 2n+1, where n is a positive integer. These numbers have special properties and are used in various mathematical applications.

2. How do we find prime numbers of given form?

There are various methods for finding prime numbers of given form. One method is to use a sieve algorithm, which involves eliminating all non-prime numbers in a given range. Another method is to use modular arithmetic and check for patterns in the remainders when dividing by certain numbers.

3. What is the significance of prime numbers of given form?

Prime numbers of given form have many applications in mathematics and computer science. They are used in cryptography, coding theory, and number theory. They also have practical applications in creating efficient algorithms and data structures.

4. Are there any famous prime numbers of given form?

Yes, there are many famous prime numbers of given form. One example is the Mersenne primes, which are prime numbers of the form 2n-1. The largest known prime number, discovered in 2018, is also a Mersenne prime. Another famous example is the Fermat primes, which are prime numbers of the form 2^(2^n) + 1.

5. Can prime numbers of given form be used in real-world problems?

Yes, prime numbers of given form have practical applications in various fields such as computer science, cryptography, and data security. They are also used in creating efficient algorithms and data structures for solving real-world problems. For example, the RSA encryption algorithm uses prime numbers of given form in its encryption and decryption processes.

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