Java Program to Find n’th Pentagonal Number

class Main
{
    public static void main(String [] args)
    {
        //n value declared
        int n = 10;
        //finding nth pentagonal number
        double f  = (3*n*(n-1)/2) + n;
        System.out.println("The nth pentagonal number is: " + f);
    }
}

Output:

The nth pentagonal number is: 145.0