Arrange the numbers 1 through 10 in the shape of a pyramid

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    Numbers Pyramid Shape
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Discussion Overview

The discussion revolves around arranging the numbers 1 through 10 in a pyramid shape, where each number at a higher level is equal to the difference of the two numbers directly below it. Participants explore various configurations, potential solutions, and the uniqueness of arrangements.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant presents an initial arrangement of the numbers in a pyramid format and questions the uniqueness of the solution.
  • Another participant provides a different arrangement and suggests that there may be multiple solutions.
  • A later post claims there are eight distinct solutions, listing them explicitly.
  • Another participant discusses the number of solutions for smaller pyramid levels, providing specific configurations for one and two levels.
  • Further exploration of three-level pyramids is presented, with a claim of eight solutions and specific placements of certain numbers at the bottom.
  • Participants express appreciation for the work done by others in the thread.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the uniqueness of the solutions, with multiple competing views on the number of valid arrangements and their configurations.

Contextual Notes

Some claims about the number of solutions depend on specific arrangements and assumptions about the placement of certain numbers, which may not be universally agreed upon.

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Arrange the numbers 1 through 10 in the shape of a pyramid (1 number at the peak, 2 numbers in the next row down, 3 in the next row, and 4 in the bottom row). The numbers must be arranged such that each number is equal to the difference of the two numbers directly below it. For example, if 5 and 1 are next to each other in the same row, then 4 must be placed on top of them.
 
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3
7 4
2 9 5
8 10 1 6
It represents a pyramid, though I'm unable to give to it a pyramidal shape
 
It looks good, but if you're reall picky you can use the code tag for fixed spacing

Code:
   3
  7 4
 2 9 5
8 A 1 6

I wonder if the solution is unique. Apparently not:

Code:
   3
  2 5
 7 9 4
8 1 A 6
 
Last edited:
There are eight solutions:

{3, 2, 5, 7, 9, 4, 8, 1, 10, 6},
{3, 4, 7, 5, 9, 2, 6, 1, 10, 8},
{3, 5, 2, 4, 9, 7, 6, 10, 1, 8},
{3, 7, 4, 2, 9, 5, 8, 10, 1, 6},
{4, 1, 5, 6, 7, 2, 9, 3, 10, 8},
{4, 2, 6, 5, 7, 1, 8, 3, 10, 9},
{4, 5, 1, 2, 7, 6, 8, 10, 3, 9},
{4, 6, 2, 1, 7, 5, 9, 10, 3, 8}

- Warren
 
For 1 level, there are 4 solutions:

2 / 1 3
2 / 3 1
1 / 2 3
1 / 3 2

3 always appears on the bottom.

For 2 levels, there are 6 solutions:

2 / 3 5 / 4 1 6
2 / 5 3 / 6 1 4
1 / 3 4 / 5 2 6
1 / 4 3 / 6 2 5
3 / 4 1 / 2 6 5
3 / 1 4 / 5 6 2

6 always appears on the bottom. 5 and 4 appear on the bottom two levels, with only one of these at the highest.

I trust there are no more than 8 solutions for 3 levels:

3 / 4 7 / 5 9 2 / 6 1 A 8
3 / 7 4 / 2 9 5 / 8 A 1 6
3 / 2 5 / 7 9 4 / 8 1 A 6
3 / 5 2 / 4 9 7 / 6 A 1 8
4 / 2 6 / 5 7 1 / 8 3 A 9
4 / 6 2 / 1 7 5 / 9 A 3 8
4 / 1 5 / 6 7 2 / 9 3 A 8
4 / 5 1 / 2 7 6 / 8 A 3 9

10 always appears on the bottom. 8 and 9 appear on the bottom two levels. (In fact 8 is always on the bottom.) 5, 6, and 7 appear on the bottom three levels, with only one of these at the highest.

What a great way to waste time...
 

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