Triangular number: Difference between revisions

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 {{Wikipedia}}
-The '''triangular number''' or '''triangle number''' (T<sub>n</sub>) gives the sum of integers starting at 1 up to n. It's the amount of objects in a dense planar equilateral arrangement.
+A '''triangular number''' or '''triangle number''' (T<sub>''n''</sub>) is a number of the form ''n''(''n'' + 1)/2 where ''n'' is a nonnegative integer. It equals the sum of integers starting at 1 up to ''n'', and is the amount of objects in a dense planar equilateral arrangement. A [[superparticular ratio]] whose numerator is a triangular number is a [[triangle-particular]].
 Triangular numbers are used in the formation of [[highschool scales]].
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 == See also ==
-* [[OEIS: A000217]]
+* {{OEIS|A000217}}
-{{stub}}
+[[Category:Elementary math]]
-[[Category:Math]]