CHALLENGE - Triangular Numbers

Question

Triangular numbers are a math series that represent the number of points in a triangle, for example the number of bowling pins. The first number is 1. The next row would have 2 for a total of 3. The next row would have 3 for a total of 6.

https://en.m.wikipedia.org/wiki/Triangular_number

The challenge is to write a program to return the nth triangular number based on user input.

For an additional challenge, print a diagram of the triangle with the number in each row represented by "X"s!

Good luck!

Answer 1

I couldn't make a nice tree with these numbers..

https://code.sololearn.com/chM4I4m8fUO5

Answer 2

Kindly post this as an assignment, as then it will gather a larger number of submissions. You will get a lesson creator badge for 10 such assignments, along with some XP.

Just open Lesson Factory and give it a shot!

Answer 3

Made code in the train on my way to work:

https://code.sololearn.com/c2LwfKJPcoyX/?ref=app

Answer 4

https://code.sololearn.com/c5IbQo408TOt/?ref=app
https://code.sololearn.com/c1N07Cf4HpNn/?ref=app

Answer 5

print(n*(n+1)/2)