
Formula for pentagonal numbers - Mathematics Stack Exchange
The n n th pentagonal number pn p n is defined algebraically as pn = n(3n−1) 2 p n = n (3 n 1) 2 for n ≥ 1 n ≥ 1. It can also be defined visually as the number of dots that can be arranged …
How to prove Euler's pentagonal theorem? Some hints will help
While there is a lot of value to the different bijective proofs known for Euler's pentagonal theorem, perhaps the proof that's easiest to see without having to draw pictures is Euler's original idea.
Is Cairo pentagonal tiling belong to pentagonal tilings type 8?
Apr 30, 2020 · I agree with you. The type 8 pentagon tiling has one degree of freedom, and although you can choose it so that clusters of four tiles form a large hexagonal shape similar to …
graph theory - Mathematics Stack Exchange
A polyhedron has all its faces either pentagons or hexagons. Show that it must have at least 12 12 pentagonal faces. I can show that it has exactly 12 12 pentagonal faces when exactly 3 3 …
A New Pentagonal Tiling? Help Me Solve the Mystery
Feb 10, 2025 · Thank you for your comment! Indeed, all convex pentagonal tilings have been mapped, and the list is believed to be complete. However, for concave pentagons, there are …
Why are $10$-sided dice not bipyramids?
Jun 12, 2019 · Commonly used 10 10 -sided dice are pentagonal trapezohedrons, as opposed to pentagonal bipyramids. Given that bipyramids are a more "obvious" shape for a fair die with an …
Proof by induction on a recursive pentagonal number algorithm
Jan 15, 2022 · I've been tasked to rewrite the following iterative function recursively: int pentagonal(int n) { int result = 0; for (int i = 1; i <= n; i++) result += 3 * i - 2; return result; } …
Understanding a solution to counting hexagons on a soccer ball
Jan 20, 2022 · Each face of a soccer ball is either a pentagon or a hexagon. Each pentagonal face is adjacent to five hexagonal faces and each hexagonal face is adjacent to three …
The minimal partition of a triangle into pentagons
Feb 22, 2023 · The question about the existence of a cycle of a given length in a $3$-connected planar graph all faces of which are pentagonal, and also attempts to solve it led to the …
The recursive formula for generalized pentagonal numbers …
Sep 1, 2019 · The recursive formula for generalized pentagonal numbers characteristic function Ask Question Asked 6 years ago Modified 4 years, 9 months ago