Generalized version of cannon ball problem

Click For Summary

Discussion Overview

The discussion revolves around the generalized version of the cannonball problem, specifically exploring whether there exist natural numbers \( n > 1 \) and \( C \) such that the sum of the first \( n \) natural numbers raised to the power \( p \) equals \( C^2 \) for all natural numbers \( p \). The scope includes theoretical exploration of Diophantine equations and potential solutions for various values of \( p \).

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that for \( p = 2 \), a known solution is \( n = 24 \) and \( C = 70 \).
  • Others mention additional solutions for \( p = 5 \) with \( n = 13, 134, \) etc., suggesting there may be more solutions.
  • There is a suggestion that the problem relates to a sequence of Diophantine equations, referencing square triangular numbers.
  • One participant expresses skepticism about finding solutions for arbitrary \( p \), citing the difficulty of Diophantine equations and referencing Hilbert's 10th problem.
  • Another participant raises the question of whether it is possible to determine the existence of \( C \) for arbitrary \( p \), even if complete solutions are not found.
  • Concerns are raised about the difficulty of proving the existence of solutions using modular arithmetic, particularly given that \( n = 1 \) always satisfies the equation.

Areas of Agreement / Disagreement

Participants express differing views on the existence of solutions for arbitrary \( p \). While some suggest that solutions may exist for specific values of \( p \), others argue that proving the existence of solutions in general is likely very challenging and may not be possible.

Contextual Notes

There are limitations regarding the assumptions made about the existence of solutions and the applicability of modular arithmetic in proving them. The discussion does not resolve these complexities.

kevin0960
Messages
12
Reaction score
0
For All p in Natural Number,
Is \exists n , n > 1, \sum^{n}_{k=1} k^p = C^2 where C is arbitary natural number (not constant) ??
 
Mathematics news on Phys.org
kevin0960 said:
For All p in Natural Number,
Is \exists n , n > 1, \sum^{n}_{k=1} k^p = C^2 where C is arbitary natural number (not constant) ??

As far as I'm aware the only solution is:
n = 24
p = 2
C = 70
 
BruceG said:
As far as I'm aware the only solution is:
n = 24
p = 2
C = 70

No, I checked with mathematica n < 100,000, p < 20

there are some solutions such as

p = 5,
n = 13, 134, etc

I think there are more solutions.. :)
 
You're trying to solve a sequence of Diophantine equations. For a famous case, search for square triangular number.
 
CRGreathouse said:
You're trying to solve a sequence of Diophantine equations. For a famous case, search for square triangular number.

Yeah, I know

But what I mean was, is it possible to find the solution for arbitary p ??
 
kevin0960 said:
But what I mean was, is it possible to find the solution for arbitary p ?

Probably not. Diophantine equations are hard, in the sense of the negative answer to Hilbert's 10th.

But for any given p it should be possible to at least formulate the problem in that form to see if anything can be discovered. So, for example, with p = 7 you have

3x^8 + 12x^7 + 14x^6 - 7x^4 + 2x^2=24y^2
 
CRGreathouse said:
Probably not. Diophantine equations are hard, in the sense of the negative answer to Hilbert's 10th.

But for any given p it should be possible to at least formulate the problem in that form to see if anything can be discovered. So, for example, with p = 7 you have

3x^8 + 12x^7 + 14x^6 - 7x^4 + 2x^2=24y^2

It seems like we cannot find C for arbitary p,

But can we know the existence of C for arbitary p ??

I don't need to find the entire solutions, just a single one.
 
It's not clear that a solution exists for a given p. If not, I don't know of an easy way to prove it -- congruence conditions won't be enough, since n = 1 works and so there are always good congruence classes mod any prime power.
 
CRGreathouse said:
It's not clear that a solution exists for a given p. If not, I don't know of an easy way to prove it -- congruence conditions won't be enough, since n = 1 works and so there are always good congruence classes mod any prime power.

Yeah, It looks almost impossible to use modular to prove...

Do you know any related article about this??
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 3 ·
Replies
3
Views
908
  • · Replies 1 ·
Replies
1
Views
500
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 4 ·
Replies
4
Views
989
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 29 ·
Replies
29
Views
6K
Replies
1
Views
2K