Hexagonal pyramidal number: Difference between revisions

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#REDIRECT [[Pyramidal number]]

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A '''hexagonal pyramidal number''' is a [[pyramidal number]] formed by adding the first ''n'' [[hexagonal number]]s. The first few hexagonal pyramidal numbers are:

:{{num|1}}, {{num|7}}, {{num|22}}, {{num|50}}, {{num|95}}, {{num|161}}, {{num|252}}, 372, 525, 715, 946, 1222, 1547, 1925 {{OEIS|A002412}}.

The ''n''th number in this sequence, representing the sum of the first ''n'' [[hexagonal number]]s, is given by the formula

:<math>\frac{n(n+1)(4n-1)}{6}.</math>

== References ==

*[http://mathworld.wolfram.com/HexagonalPyramidalNumber.html Hexagonal pyramidal number at MathWorld]

{{Figurate numbers}}

{{Classes of natural numbers}}

[[Category:Figurate numbers]]

{{numtheory-stub}}