# Pascal triangle

A table of the binomial coefficients. In this table, there are 1's at the lateral sides of an equilateral triangle and each of the remaining numbers is the sum of the two numbers above it to the left and right:

$$\begin{array}{c} {} \\ {} \\ {} \\ {} \\ {} \\ {} \\ 1 \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ {} \\ {} \\ 1 \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ {} \\ 1 \\ {} \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ 1 \\ {} \\ 5 \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ 1 \\ {} \\ 4 \\ {} \\ \cdot \end{array} \ \begin{array}{c} {} \\ 1 \\ {} \\ 3 \\ {} \\ 10 \\ \cdot \end{array} \ \begin{array}{c} 1 \\ {} \\ 2 \\ {} \\ 6 \\ {} \\ \cdot \end{array} \ \begin{array}{c} {} \\ 1 \\ {} \\ 3 \\ {} \\ 10 \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ 1 \\ {} \\ 4 \\ {} \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ 1 \\ {} \\ 5 \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ {} \\ 1 \\ {} \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ {} \\ {} \\ 1 \\ \cdot \end{array} \ \begin{array}{c} {} \\ {} \\ {} \\ {} \\ {} \\ {} \\ 1 \end{array}$$

In the row numbered $n+1$ there appear the coefficients of the expansion of the binomial $(a+b)^{n}$. The triangular table presented by B. Pascal in his "Treatise on an arithmetical triangle" (1654) differs from the one described above by a rotation through $45^\circ$.

Tables for the representation of the binomial coefficients were known even earlier.

The binomial coefficients triangle (arithmetical triangle) was, e.g., known to N. Tartaglia, M. Stifel and S. Stevin long before Pascal. Still earlier it appeared in the Chinese mathematical literature (Chu Shih-Chieh, "precious mirror" , Yang Hui, before 1300) and in the Arabian literature (Al-Kashi, early 1400's). In the Western literature the triangle occurs printed on the title page of Stifel's Arithmetica integra, published in 1544, almost a century before the birth of Pascal.

How to Cite This Entry:
Pascal triangle. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Pascal_triangle&oldid=54224
This article was adapted from an original article by V.I. Nechaev (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article