Arithmetic & Number Theory
Triangular Number
Sum of the first n natural numbers.
Formula
Formula
Tn = n(n+1)2
Variables
| Symbol | Definition | Type & range | Units | Role |
|---|---|---|---|---|
| n | index | integer (ℤ) | — | input |
| Tₙ | n-th triangular number | computed result | — | result |
Try it yourself
Interactive calculator
Worked examples
Example 1
Givenn = 10
Result55
Example 2
Givenn = 100
Result5050