Pentagonal numbers

The problem

A pentagonal number is defined as n(3n–1)/2 for n = 1, 2, . . ., and so on. Therefore, the first few numbers are 1, 5, 12, 22, . . .. Write a method with the following header that returns a pentagonal number: public static int getPentagonalNumber(int n). Write a test program that uses this method to display the first 100 pentagonal numbers with 10 numbers on each line.

Breaking it down

public static void main(String[] args) {

    IntStream.rangeClosed(1, 100).map(i -> getPentagonalNumber(i))
            .forEach(System.out::println);
}

public static int getPentagonalNumber(int n) {
    return n * (3 * n - 1) / 2;
}

Output