A triangular number is one that fits the formula n (n+1)/2, such as 1, 3, 6, 10, 15. Even if I told you Harry’s triangular number you would not be able to deduce with certainty which perfect ...

Test your knowledge of taxicab geometry, triangular numbers, the golden ratio and more. Credit... Supported by By Steven Strogatz “Math, Revealed,” our four-part series exploring the ...

Feng Qi, Qing Zou, Bai-Ni Guo, THE INVERSE OF A TRIANGULAR MATRIX AND SEVERAL IDENTITIES OF THE CATALAN NUMBERS, Applicable Analysis and Discrete Mathematics, Vol. 13, No. 2 (October 2019), pp.

But it was triangular numbers that got the ball rolling in the first place. Sign up here for the weekly Science Times newsletter.

2) It is a triangular number, that is of the series 1,3,6,10,15 … 3) It is a cube, or a cube plus 3. 4) It may be written as a single-digit prime followed by a two-digit prime.