Triangular Number Reference Values

Calculate the nth triangular number using T(n) = n(n + 1) / 2.

Author

Dr. Lars Eriksson

Math editorial contributor

Swedish environmental economist from Stockholm School of Economics, advisor to the EU on carbon pricing policy

Reviewed for accuracy by

Prof. Kenji Tanaka

Math content reviewer

Japanese materials scientist at Kyoto University, known for breakthroughs in sustainable polymer research

Last updatedFebruary 22, 2026

PublishedFebruary 22, 2026

Table of Contents

  1. All value pages
  2. Reference table
  3. FAQs
  4. Methodology and review
  5. Related conversions

Reference Value Index

This page lists 23 reference values for quick browsing and lookup.

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All Reference Values

Reference Table

Triangular Number reference values
nT(n)
0 Integer n0 Triangular Number
1 Integer n1 Triangular Number
2 Integer n3 Triangular Number
3 Integer n6 Triangular Number
4 Integer n10 Triangular Number
5 Integer n15 Triangular Number
6 Integer n21 Triangular Number
7 Integer n28 Triangular Number
8 Integer n36 Triangular Number
9 Integer n45 Triangular Number
10 Integer n55 Triangular Number
12 Integer n78 Triangular Number
15 Integer n120 Triangular Number
20 Integer n210 Triangular Number
25 Integer n325 Triangular Number
50 Integer n1,275 Triangular Number
75 Integer n2,850 Triangular Number
100 Integer n5,050 Triangular Number
250 Integer n31,375 Triangular Number
500 Integer n125,250 Triangular Number
1,000 Integer n500,500 Triangular Number
5,000 Integer n12,502,500 Triangular Number
10,000 Integer n50,005,000 Triangular Number

Frequently Asked Questions

Frequently asked questions for Triangular Number and its reference values.

What does the Triangular Number calculator do?

It helps with counting pair combinations, stacked objects, and arithmetic series totals from 1 to n.

What formula does the Triangular Number calculator use?

Triangular number T(n) = n(n + 1) / 2.

What inputs are valid?

n must be a non-negative integer. The calculator caps n to preserve exact safe integer output formatting.

When would I use this?

counting pair combinations, stacked objects, and arithmetic series totals from 1 to n

Methodology and Review

Each row on this page links to a value detail page derived from the same conversion data file as the main calculator and reference table. This reduces inconsistencies across page variants.

Editorial metadata and structured data are rendered across the converter page and linked value pages. Review policies are documented in our review process and editorial policy.