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#REDIRECT [[Pyramidal number]]
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{{merge|Pentagonal pyramidal number|Heptagonal pyramidal number|target=Pyramidal number|discuss=Talk:Pyramidal number#Merger proposal|date=November 2021}}
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}}
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