All examples in this Problem are groups of black dots.

The nth triangular number is the sum over the natural numbers from 1 to n, where n > 0. Note: 0 is the 0th triangular number. The first few triangular numbers are 0, 1, 3 (= 1+2) and 6 (= 1+2+3)

All examples in this Problem are groups of black dots.

The examples are all arranged in a way that makes it easy for a human to understand.

The nth triangular number is the sum over the natural numbers from 1 to n, where n > 0. Note: 0 is the 0th triangular number. The first few triangular numbers are 0, 1, 3 (= 1+2) and 6 (= 1+2+3)

All examples in this Problem are groups of black dots.

The examples are all arranged in a way that makes it easy for a human to understand.

The nth triangular number is the sum over the natural numbers from 1 to n, where n > 0. Note: 0 is the 0th triangular number.

All examples in this Problem are groups of black dots.

The nth triangular number is the sum over the natural numbers from 1 to n, where n > 0. Note: 0 is the 0th triangular number.

All examples in this Problem are groups of black dots.

A triangular number is a number of the form n + (n-1) + (n-2) + ... + 1, where n is some left integer. The smallest triangular numbers are 1, 3 (= 1 + 2) and 6 (= 1 + 2 + 3)

Triangular number of dots vs. non-triangular number of dots

Leo Crabbe