any integer that is the sum of n natural numbers between 1 and n

English - English

Definition of any integer that is the sum of n natural numbers between 1 and n in English English dictionary

triangular number

Ten is a triangular number being the sum of 1, 2, 3, and 4.

Hyphenation

a·ny in·te·ger that I·s the sum of n na·tu·ral Num·bers be·tween 1 and n