Inaugural Series

Todd Southworth, on only his 2nd sign, and the 173rd sign ever submitted to Road Sign Math brings us the very first series sign! The dozens of seekers of mathematically significant roadsigns have found numerous basic and advanced signs, and even a lot of constant, but this is our very first series sign. Congratulations to Mr. Southworth!



Mr. Southworth spent a while trying to solve this sign, and then it hit him! This sign contains the 3rd, 4th and 5th Triangular numbers.

$${1\over2}n(n+1)$$

This sign is on CA-210 near the Day Creek Boulevard exit in Rancho Cucamonga, California.