What are these figurate numbers ?

The previous page shows one of the most famous examples illustrating this ancient shape of numbers: the Tetraktys.

• The triangle is made of 10 pebbles, with a base of 4.
• The formula which leads to this result is a very easy one:

  • given n, the basic number: [ n * ( n + 1 )] / 2
    • i.e., fot the Tetraktys : [ 4 * ( 4 + 1 )] / 2

It is possible to aply this formula to each degree of the circle.

And it is also possible to go further and to consider all regular polygons which can be inscribed in the circle.

You can find all charts for traditional and centred figured numbers in these pages.

You will also find simple formulas for all calculations on the page *form*.

Besides, you can have all these bases. Please refer to the page *order*.

Do not hesitate to tell me about your comments.

NB - Do not try to print all these charts.
Except if you have a fairly strong printer, time and over 4,000 pages.