isPronic

A pronic number (also known as oblongnumber, rectangular number or heteromecic number), is a number which is the product of two consecutive integers, i.e. it can be represented as x * (x + 1) for some integer x. The first few pronic numbers are:

0, 2, 6, 12, 20, 30, 42...

Here’s why:

• 0 = 0 × 1
• 2 = 1 × 2
• 6 = 2 × 3
• 12 = 3 × 4
• 20 = 4 × 5
• 30 = 5 × 6
• 42 = 6 × 7

Your task is to write a function isPronic which checks whether the number n is a pronic number and returns true if it is and falseotherwise.

Example

• For n = 0, the output should be isPronic(n) = true.

• For n = 1, the output should be isPronic(n) = false.

Input/Output

• [execution time limit] 0.5 seconds

• [input] integer n

  Constraints:
  
  0 ≤ n ≤ 225.

• [output] boolean

  • true if n is a pronic number, false otherwise.