Last week I made a post about Triangular Numbers. I posted a request for a new integer sequence on OEIS, which eventually got merged with an existing sequence, The Triangular Matchstick Numbers: https://oeis.org/A045943.

I love math.

Here are the Triangular Matchstick Number Formulas:

**Recurrence Relation:**

` a(0) = 0`

a(n) = a(n-1) + 3*n

**Generating Function:**

a(n) = 3*n

---------

(1-n)^3