A Pixellated Sierpinski triangle
Posted: Tue Mar 03, 2026 7:38 am
I couldn't find a place to post this thread, so it will have to go here for the moment. It followed from a discussion about pixellated Sierpin ski triangles. I did some work on them this morning and came up with what I believe to be the closest approximation in numerical geometry to a Sierpinski triangle in plane geometry.
I started with triangle 1 (T1) and kept on doubling to give T2, T4, T8, T16, T32, T64 . . .
It has several interesting features
1. It corresponds to removing all the even numbers in Pascal's triangle.
2. The first triangle from which a unit could be removed was T4, giving a crude Sierpinski triangle of 9 units. The triangles created thereafter have multiples of 3 units: 27, 81, 243, 729 . . . .
3. The index of the largest triangle that can be cut from the centre at each stage corresponds to the number counts down to each row of Pascal's triangle (details in the image).
4. The perfect numbers are all accommodated and I show the first three: 6, 28, 496. The next one is 8128, which the next stage produces.
5. The index of each triangle corresponds to the row counts in Pascal's triangle (details in the image).
6. These are also the Mersene numbers (2^n - 1): 1, 3, 7, 15, 31.
7. The first three perfect numbers correspond to three Mersene primes 3, 7, 31. The next one corresponds to another Mersene prime, 127 (T127 is 8128).
Note: I just checked and the next perfect number beyond 8128 is 33550336, which like all of them is triangular. Its base is 8191, also a Mersene orime. So I’m guessing that all perfect numbers will fit onto this template, with enough doublings, and have a prime number index.p (I’m also guessing this is well known among number theorists!) I must check and see if that has been proven.
Note 2: I was right. It’s a well known result in number theory. Nice to see it visually though, and from the simplest of beginnings.
8. I believe the only complete Sierpinski triangle will be cut from T(infinity), but that's just an amateur's intuitive guess.
9. The area of the Sierpinski triangle after infinite iterations is zero, and so the fraction no. units ST/no. units T will tend to zero as the sequence progresses. The first few ratios are 0.9, 0.75, 0.595.., 0.460.., 0.350.., 0.264..,
Anyway, apologies for any lack of mathematical formalism. I just thought it was interesting and some of you might like to see the first few natural Sierpinski triangle approximations. There are other types, but this is the closest to the fractal in plane geometry,
It was worth doing for itself, but also because I believe I have found two Sierpinski triangles (though not in this 'ideal' sequence) within the Hebrew Bible's first verse, as a mirrored pair.
I started with triangle 1 (T1) and kept on doubling to give T2, T4, T8, T16, T32, T64 . . .
It has several interesting features
1. It corresponds to removing all the even numbers in Pascal's triangle.
2. The first triangle from which a unit could be removed was T4, giving a crude Sierpinski triangle of 9 units. The triangles created thereafter have multiples of 3 units: 27, 81, 243, 729 . . . .
3. The index of the largest triangle that can be cut from the centre at each stage corresponds to the number counts down to each row of Pascal's triangle (details in the image).
4. The perfect numbers are all accommodated and I show the first three: 6, 28, 496. The next one is 8128, which the next stage produces.
5. The index of each triangle corresponds to the row counts in Pascal's triangle (details in the image).
6. These are also the Mersene numbers (2^n - 1): 1, 3, 7, 15, 31.
7. The first three perfect numbers correspond to three Mersene primes 3, 7, 31. The next one corresponds to another Mersene prime, 127 (T127 is 8128).
Note: I just checked and the next perfect number beyond 8128 is 33550336, which like all of them is triangular. Its base is 8191, also a Mersene orime. So I’m guessing that all perfect numbers will fit onto this template, with enough doublings, and have a prime number index.p (I’m also guessing this is well known among number theorists!) I must check and see if that has been proven.
Note 2: I was right. It’s a well known result in number theory. Nice to see it visually though, and from the simplest of beginnings.
8. I believe the only complete Sierpinski triangle will be cut from T(infinity), but that's just an amateur's intuitive guess.
9. The area of the Sierpinski triangle after infinite iterations is zero, and so the fraction no. units ST/no. units T will tend to zero as the sequence progresses. The first few ratios are 0.9, 0.75, 0.595.., 0.460.., 0.350.., 0.264..,
Anyway, apologies for any lack of mathematical formalism. I just thought it was interesting and some of you might like to see the first few natural Sierpinski triangle approximations. There are other types, but this is the closest to the fractal in plane geometry,
It was worth doing for itself, but also because I believe I have found two Sierpinski triangles (though not in this 'ideal' sequence) within the Hebrew Bible's first verse, as a mirrored pair.