**Pronic number in Java**:

A Pronic number is a number which is the product of two consecutive integers, that is n*(n+1), Pronic number also express as (n² + n). A Pronic number is also known as oblong number, rectangular number or heteromecic number. There are 99 pronic numbers below 10,000.

**Mathematical Properties****:**

Pronic numbers are even number. Therefore, all pronic numbers are multiples of 2, but 2 is composite number. There are two reasons for pronic number are even.

**1.** If N=i*(i+1), then either i or (i + 1) has to be an even number. Since an even number multiplied by any integer is still an even number, so pronic numbers are even.

**2.** Pronic numbers are twice of triangular numbers. The picture showing 12 is actually 2 × (3 + 2 + 1).

There are no odd pronic number but there is a prime pronic number, the only even prime, 2.

Example:

0, 2, 6, 12, 20, 30, 42, 56, 72, 90, 110, 132, 156…

import java.util.*; class PronicNumber { public static void main(String args[]) { int a, i, j=0 Scanner cy = new Scanner(System.in); System.out.print("Enter a number : "); //get a number to check pronic a = cy.nextInt(); for(i=1; i<=a; i++) { if(i*(i+1) == a) //check number is multiple of two consecutive number or not { j = 1; break; } } if(j == 1) //print number is pronic or not System.out.println(a+" is a Pronic Number."); else System.out.println(a+" is not a Pronic Number."); } }

Output:

Enter a number: 72

72 is a Pronic Number.

Enter a number: 112

112 is not a Pronic Number.

Enter a number : 110

110 is a Pronic Number.

Enter a number : 73

73 is not a Pronic Number.

**Pronic number code in Java, BlueJ, C**