Pyramidal number: Difference between revisions

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A pyramidal number is a figurate number that represents a pyramid with a base and a given number of sides. The term is most often used to refer to square pyramidal numbers, which have four sides, but it can also refer to:

Triangular pyramidal number (three sides)
Square pyramidal number (four sides)
Pentagonal pyramidal number (five sides)
Hexagonal pyramidal number (six sides)
Heptagonal pyramidal number (seven sides)

The formula for a r-gonal pyramid number is:

X={\frac {3n^{2}+n^{3}(r-2)-n(r-5)}{6}}

where r is a natural number greater or equal to 3.

Revision as of 11:54, 2 September 2013 edit Gherghel (talk \| contribs) 54 edits No edit summary Tag: Visual edit ← Previous edit		Revision as of 12:09, 2 September 2013 edit undo Gherghel (talk \| contribs) 54 edits No edit summary Next edit →
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	:<math>X= \frac{3n^2 + n^3(r-2) - n(r-5)}{6}</math>		:<math>X= \frac{3n^2 + n^3(r-2) - n(r-5)}{6}</math>
	where '''r''' is a natural number greater or equal to 3.[[Category:Figurate numbers]]		where '''r''' is a [[natural number]] greater or equal to 3.[[Category:Figurate numbers]]