triangular numbers

plural noun

Definition of triangular numbers

: the successive sums n(n + 1)/2 where n = 1, 2, 3, … of the first n natural numbers 1, 3, 6, 10, 15, … representable by dots arranged in triangles

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First Known Use of triangular numbers

1795, in the meaning defined above

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Time Traveler for triangular numbers

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The first known use of triangular numbers was in 1795

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Cite this Entry

“Triangular numbers.” Dictionary, Merriam-Webster, Accessed 5 Aug. 2020.

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