Category:Square Numbers

From ProofWiki
Jump to navigation Jump to search

This category contains results about Square Numbers.
Definitions specific to this category can be found in Definitions/Square Numbers.

Square numbers are those denumerating a collection of objects which can be arranged in the form of a square.


They can be denoted:

$S_1, S_2, S_3, \ldots$


Definition 1

An integer $n$ is classified as a square number if and only if:

$\exists m \in \Z: n = m^2$

where $m^2$ denotes the integer square function.


Euclid's Definition

In the words of Euclid:

A square number is equal multiplied by equal, or a number which is contained by two equal numbers.

(The Elements: Book $\text{VII}$: Definition $18$)


Definition 2

$S_n = \begin {cases}

0 & : n = 0 \\ S_{n - 1} + 2 n - 1 & : n > 0 \end {cases}$


Definition 3

$\ds S_n = \sum_{i \mathop = 1}^n \paren {2 i - 1} = 1 + 3 + 5 + \cdots + \paren {2 n - 1}$


Definition 4

$\forall n \in \N: S_n = \map P {4, n} = \begin{cases}

0 & : n = 0 \\ \map P {4, n - 1} + 2 \paren {n - 1} + 1 & : n > 0 \end{cases}$ where $\map P {k, n}$ denotes the $k$-gonal numbers.

Subcategories

This category has the following 30 subcategories, out of 30 total.

Pages in category "Square Numbers"

The following 126 pages are in this category, out of 126 total.

S