Hexagonal pyramidal number

A hexagonal pyramidal number is a number formed by adding the first few hexagonal numbers. The first few numbers are 1, 7, 22, 50, 95; these nubmers have the form ${\displaystyle n(n+1)(4n-1)/6}$.

References

Hexagonal pyramidal number at MathWorld

You must add a |reason= parameter to this Cleanup template – replace it with {{Cleanup|reason=<Fill reason here>}}, or remove the Cleanup template.