A triangular number is a number of circles in an equilateral triangle evenly filled with circles. They’re called as triangular numbers because they can be made into triangular shapes.

Program

Write a program to calculate the sum of all the triangular numbers less than equal to given input number N.

Input

  • The number N up to which triangular numbers have to be computed.

Output 

  • The sum of the all the triangular numbers.

Assumptions

  •  N is > 0

Algorithm

The first triangular number is formed by adding 1 to 0, then adding 2 to 1st triangular number, adding 3 to the 2nd triangular number and so on. If N = 25, the triangular numbers less than 25 are 1,3,6,10,15,21 and there sum is 1+3+6+10+15+21=57

Test cases

No
Input N (Upto to)
Intermediate (Triangular Numbers)
Output (Sum)
1
25
1, 3, 6, 10, 15, 21
57
2
501, 3, 6, 10, 15, 21, 28, 36, 45
166
3
1001, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91
456

Instructions 

  • Accept the number N up to with (not including), we have to create the triangular numbers as input via the command line arguments.
  • Write the logic to compute the triangle numbers and add them up.
  • Display the resulting sum.